[{"title":"Directed percolation and the transition to turbulence","author":[{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof"}],"external_id":{"isi":["000890148700002"]},"article_processing_charge":"No","user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"mla":"Hof, Björn. “Directed Percolation and the Transition to Turbulence.” Nature Reviews Physics, vol. 5, Springer Nature, 2023, pp. 62–72, doi:10.1038/s42254-022-00539-y.","ama":"Hof B. Directed percolation and the transition to turbulence. Nature Reviews Physics. 2023;5:62-72. doi:10.1038/s42254-022-00539-y","apa":"Hof, B. (2023). Directed percolation and the transition to turbulence. Nature Reviews Physics. Springer Nature. https://doi.org/10.1038/s42254-022-00539-y","short":"B. Hof, Nature Reviews Physics 5 (2023) 62–72.","ieee":"B. Hof, “Directed percolation and the transition to turbulence,” Nature Reviews Physics, vol. 5. Springer Nature, pp. 62–72, 2023.","chicago":"Hof, Björn. “Directed Percolation and the Transition to Turbulence.” Nature Reviews Physics. Springer Nature, 2023. https://doi.org/10.1038/s42254-022-00539-y.","ista":"Hof B. 2023. Directed percolation and the transition to turbulence. Nature Reviews Physics. 5, 62–72."},"date_published":"2023-01-01T00:00:00Z","doi":"10.1038/s42254-022-00539-y","date_created":"2023-01-12T12:10:18Z","page":"62-72","day":"01","publication":"Nature Reviews Physics","isi":1,"year":"2023","quality_controlled":"1","publisher":"Springer Nature","department":[{"_id":"BjHo"}],"date_updated":"2023-08-01T12:50:48Z","status":"public","keyword":["General Physics and Astronomy"],"type":"journal_article","article_type":"original","_id":"12165","volume":5,"language":[{"iso":"eng"}],"publication_identifier":{"eissn":["2522-5820"]},"publication_status":"published","month":"01","intvolume":" 5","scopus_import":"1","oa_version":"None","abstract":[{"lang":"eng","text":"It may come as a surprise that a phenomenon as ubiquitous and prominent as the transition from laminar to turbulent flow has resisted combined efforts by physicists, engineers and mathematicians, and remained unresolved for almost one and a half centuries. In recent years, various studies have proposed analogies to directed percolation, a well-known universality class in statistical mechanics, which describes a non-equilibrium phase transition from a fluctuating active phase into an absorbing state. It is this unlikely relation between the multiscale, high-dimensional dynamics that signify the transition process in virtually all flows of practical relevance, and the arguably most basic non-equilibrium phase transition, that so far has mainly been the subject of model studies, which I review in this Perspective."}]},{"project":[{"name":"Revisiting the Turbulence Problem Using Statistical Mechanics: Experimental Studies on Transitional and Turbulent Flows","grant_number":"662960","_id":"238598C6-32DE-11EA-91FC-C7463DDC885E"}],"article_number":"A10","title":"Symmetry-reduced dynamic mode decomposition of near-wall turbulence","author":[{"id":"0BE7553A-1004-11EA-B805-18983DDC885E","first_name":"Elena","last_name":"Marensi","full_name":"Marensi, Elena"},{"full_name":"Yalniz, Gökhan","orcid":"0000-0002-8490-9312","last_name":"Yalniz","first_name":"Gökhan","id":"66E74FA2-D8BF-11E9-8249-8DE2E5697425"},{"orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof","first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Budanur","orcid":"0000-0003-0423-5010","full_name":"Budanur, Nazmi B","first_name":"Nazmi B","id":"3EA1010E-F248-11E8-B48F-1D18A9856A87"}],"external_id":{"isi":["000903336600001"],"arxiv":["2101.07516"]},"article_processing_charge":"Yes (via OA deal)","user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"mla":"Marensi, Elena, et al. “Symmetry-Reduced Dynamic Mode Decomposition of near-Wall Turbulence.” Journal of Fluid Mechanics, vol. 954, A10, Cambridge University Press, 2023, doi:10.1017/jfm.2022.1001.","ieee":"E. Marensi, G. Yalniz, B. Hof, and N. B. Budanur, “Symmetry-reduced dynamic mode decomposition of near-wall turbulence,” Journal of Fluid Mechanics, vol. 954. Cambridge University Press, 2023.","short":"E. Marensi, G. Yalniz, B. Hof, N.B. Budanur, Journal of Fluid Mechanics 954 (2023).","ama":"Marensi E, Yalniz G, Hof B, Budanur NB. Symmetry-reduced dynamic mode decomposition of near-wall turbulence. Journal of Fluid Mechanics. 2023;954. doi:10.1017/jfm.2022.1001","apa":"Marensi, E., Yalniz, G., Hof, B., & Budanur, N. B. (2023). Symmetry-reduced dynamic mode decomposition of near-wall turbulence. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2022.1001","chicago":"Marensi, Elena, Gökhan Yalniz, Björn Hof, and Nazmi B Budanur. “Symmetry-Reduced Dynamic Mode Decomposition of near-Wall Turbulence.” Journal of Fluid Mechanics. Cambridge University Press, 2023. https://doi.org/10.1017/jfm.2022.1001.","ista":"Marensi E, Yalniz G, Hof B, Budanur NB. 2023. Symmetry-reduced dynamic mode decomposition of near-wall turbulence. Journal of Fluid Mechanics. 954, A10."},"publisher":"Cambridge University Press","quality_controlled":"1","oa":1,"acknowledgement":"E.M. acknowledges funding from the ISTplus fellowship programme. G.Y. and B.H. acknowledge\r\na grant from the Simons Foundation (662960, BH).","date_published":"2023-01-10T00:00:00Z","doi":"10.1017/jfm.2022.1001","date_created":"2023-01-08T23:00:53Z","day":"10","publication":"Journal of Fluid Mechanics","isi":1,"has_accepted_license":"1","year":"2023","status":"public","article_type":"original","type":"journal_article","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"_id":"12105","department":[{"_id":"BjHo"}],"file_date_updated":"2023-02-02T12:34:54Z","ddc":["530"],"date_updated":"2023-08-01T12:53:23Z","month":"01","intvolume":" 954","scopus_import":"1","oa_version":"Published Version","abstract":[{"lang":"eng","text":"Data-driven dimensionality reduction methods such as proper orthogonal decomposition and dynamic mode decomposition have proven to be useful for exploring complex phenomena within fluid dynamics and beyond. A well-known challenge for these techniques is posed by the continuous symmetries, e.g. translations and rotations, of the system under consideration, as drifts in the data dominate the modal expansions without providing an insight into the dynamics of the problem. In the present study, we address this issue for fluid flows in rectangular channels by formulating a continuous symmetry reduction method that eliminates the translations in the streamwise and spanwise directions simultaneously. We demonstrate our method by computing the symmetry-reduced dynamic mode decomposition (SRDMD) of sliding windows of data obtained from the transitional plane-Couette and turbulent plane-Poiseuille flow simulations. In the former setting, SRDMD captures the dynamics in the vicinity of the invariant solutions with translation symmetries, i.e. travelling waves and relative periodic orbits, whereas in the latter, our calculations reveal episodes of turbulent time evolution that can be approximated by a low-dimensional linear expansion."}],"volume":954,"license":"https://creativecommons.org/licenses/by/4.0/","file":[{"relation":"main_file","access_level":"open_access","content_type":"application/pdf","success":1,"checksum":"9224f987caefe5dd85a70814d3cce65c","file_id":"12489","creator":"dernst","file_size":1931647,"date_updated":"2023-02-02T12:34:54Z","file_name":"2023_JourFluidMechanics_Marensi.pdf","date_created":"2023-02-02T12:34:54Z"}],"language":[{"iso":"eng"}],"publication_identifier":{"eissn":["1469-7645"],"issn":["0022-1120"]},"publication_status":"published"},{"intvolume":" 55","month":"01","scopus_import":"1","oa_version":"Published Version","abstract":[{"text":"The dissolution of minute concentration of polymers in wall-bounded flows is well-known for its unparalleled ability to reduce turbulent friction drag. Another phenomenon, elasto-inertial turbulence (EIT), has been far less studied even though elastic instabilities have already been observed in dilute polymer solutions before the discovery of polymer drag reduction. EIT is a chaotic state driven by polymer dynamics that is observed across many orders of magnitude in Reynolds number. It involves energy transfer from small elastic scales to large flow scales. The investigation of the mechanisms of EIT offers the possibility to better understand other complex phenomena such as elastic turbulence and maximum drag reduction. In this review, we survey recent research efforts that are advancing the understanding of the dynamics of EIT. We highlight the fundamental differences between EIT and Newtonian/inertial turbulence from the perspective of experiments, numerical simulations, instabilities, and coherent structures. Finally, we discuss the possible links between EIT and elastic turbulence and polymer drag reduction, as well as the remaining challenges in unraveling the self-sustaining mechanism of EIT.","lang":"eng"}],"issue":"1","volume":55,"language":[{"iso":"eng"}],"file":[{"success":1,"checksum":"2666aa3af2a25252d35eb8681d3edff7","file_id":"12690","relation":"main_file","access_level":"open_access","content_type":"application/pdf","file_name":"2023_AnnReviewFluidMech_Dubief.pdf","date_created":"2023-02-27T09:23:02Z","creator":"dernst","file_size":4036706,"date_updated":"2023-02-27T09:23:02Z"}],"publication_status":"published","publication_identifier":{"issn":["0066-4189"],"eissn":["1545-4479"]},"status":"public","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"type":"journal_article","article_type":"original","_id":"12681","department":[{"_id":"BjHo"}],"file_date_updated":"2023-02-27T09:23:02Z","ddc":["530"],"date_updated":"2023-08-01T13:19:47Z","oa":1,"quality_controlled":"1","publisher":"Annual Reviews","acknowledgement":"Part of the material presented here is based upon work supported by the National Science Foundation CBET (Chemical, Bioengineering, Environmental and Transport Systems) award 1805636 (to Y.D.), the Binational Science Foundation award 2016145 (to Y.D. and Victor Steinberg), a FRIA (Fund for Research Training in Industry and Agriculture) grant of the Belgian F.R.S.-FNRS (National Fund for Scientific Research) (to V.E.T.), the Marie Curie FP7 Career Integration grant PCIG10-GA-2011-304073 (to V.E.T.), and the Fonds spéciaux pour la recherche grant C-13/19 of the University of Liege (to V.E.T.). Computational resources have been provided by the Consortium des Équipements de Calcul Intensif (CECI) funded by the Belgian F.R.S.-FNRS, the Vermont Advanced Computing Center (VACC), the Partnership for Advanced Computing in Europe (PRACE), and the Tier-1 supercomputer of the Fédération Wallonie-Bruxelles funded by the Walloon Region (grant agreement 117545).","date_created":"2023-02-26T23:01:01Z","date_published":"2023-01-19T00:00:00Z","doi":"10.1146/annurev-fluid-032822-025933","page":"675-705","publication":"Annual Review of Fluid Mechanics","day":"19","year":"2023","isi":1,"has_accepted_license":"1","title":"Elasto-inertial turbulence","external_id":{"isi":["000915418100026"]},"article_processing_charge":"No","author":[{"last_name":"Dubief","full_name":"Dubief, Yves","first_name":"Yves"},{"first_name":"Vincent E.","last_name":"Terrapon","full_name":"Terrapon, Vincent E."},{"last_name":"Hof","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87"}],"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"apa":"Dubief, Y., Terrapon, V. E., & Hof, B. (2023). Elasto-inertial turbulence. Annual Review of Fluid Mechanics. Annual Reviews. https://doi.org/10.1146/annurev-fluid-032822-025933","ama":"Dubief Y, Terrapon VE, Hof B. Elasto-inertial turbulence. Annual Review of Fluid Mechanics. 2023;55(1):675-705. doi:10.1146/annurev-fluid-032822-025933","ieee":"Y. Dubief, V. E. Terrapon, and B. Hof, “Elasto-inertial turbulence,” Annual Review of Fluid Mechanics, vol. 55, no. 1. Annual Reviews, pp. 675–705, 2023.","short":"Y. Dubief, V.E. Terrapon, B. Hof, Annual Review of Fluid Mechanics 55 (2023) 675–705.","mla":"Dubief, Yves, et al. “Elasto-Inertial Turbulence.” Annual Review of Fluid Mechanics, vol. 55, no. 1, Annual Reviews, 2023, pp. 675–705, doi:10.1146/annurev-fluid-032822-025933.","ista":"Dubief Y, Terrapon VE, Hof B. 2023. Elasto-inertial turbulence. Annual Review of Fluid Mechanics. 55(1), 675–705.","chicago":"Dubief, Yves, Vincent E. Terrapon, and Björn Hof. “Elasto-Inertial Turbulence.” Annual Review of Fluid Mechanics. Annual Reviews, 2023. https://doi.org/10.1146/annurev-fluid-032822-025933."}},{"publication_status":"published","publication_identifier":{"issn":["0066-4189"]},"language":[{"iso":"eng"}],"file":[{"content_type":"application/pdf","access_level":"open_access","relation":"main_file","checksum":"f99ef30f76cabc9e5e1946b380c16db4","file_id":"12691","success":1,"date_updated":"2023-02-27T09:35:52Z","file_size":4769537,"creator":"dernst","date_created":"2023-02-27T09:35:52Z","file_name":"2023_AnnReviewFluidMech_Avila.pdf"}],"volume":55,"abstract":[{"lang":"eng","text":"Since the seminal studies by Osborne Reynolds in the nineteenth century, pipe flow has served as a primary prototype for investigating the transition to turbulence in wall-bounded flows. Despite the apparent simplicity of this flow, various facets of this problem have occupied researchers for more than a century. Here we review insights from three distinct perspectives: (a) stability and susceptibility of laminar flow, (b) phase transition and spatiotemporal dynamics, and (c) dynamical systems analysis of the Navier—Stokes equations. We show how these perspectives have led to a profound understanding of the onset of turbulence in pipe flow. Outstanding open points, applications to flows of complex fluids, and similarities with other wall-bounded flows are discussed."}],"oa_version":"Published Version","scopus_import":"1","intvolume":" 55","month":"01","date_updated":"2023-08-01T13:20:30Z","ddc":["530"],"department":[{"_id":"BjHo"}],"file_date_updated":"2023-02-27T09:35:52Z","_id":"12682","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"type":"journal_article","article_type":"original","status":"public","year":"2023","has_accepted_license":"1","isi":1,"publication":"Annual Review of Fluid Mechanics","day":"19","page":"575-602","date_created":"2023-02-26T23:01:01Z","date_published":"2023-01-19T00:00:00Z","doi":"10.1146/annurev-fluid-120720-025957","acknowledgement":"The authors are very grateful to Laurette Tuckerman for her helpful comments. This work was supported by grants from the Simons Foundation (grant numbers 662985, D.B., and 662960, B.H.) and the Priority Programme “SPP 1881: Turbulent Superstructures” of the Deutsche Forschungsgemeinschaft (grant number AV120/3-2 to M.A.).","oa":1,"quality_controlled":"1","publisher":"Annual Reviews","citation":{"ieee":"M. Avila, D. Barkley, and B. Hof, “Transition to turbulence in pipe flow,” Annual Review of Fluid Mechanics, vol. 55. Annual Reviews, pp. 575–602, 2023.","short":"M. Avila, D. Barkley, B. Hof, Annual Review of Fluid Mechanics 55 (2023) 575–602.","apa":"Avila, M., Barkley, D., & Hof, B. (2023). Transition to turbulence in pipe flow. Annual Review of Fluid Mechanics. Annual Reviews. https://doi.org/10.1146/annurev-fluid-120720-025957","ama":"Avila M, Barkley D, Hof B. Transition to turbulence in pipe flow. Annual Review of Fluid Mechanics. 2023;55:575-602. doi:10.1146/annurev-fluid-120720-025957","mla":"Avila, Marc, et al. “Transition to Turbulence in Pipe Flow.” Annual Review of Fluid Mechanics, vol. 55, Annual Reviews, 2023, pp. 575–602, doi:10.1146/annurev-fluid-120720-025957.","ista":"Avila M, Barkley D, Hof B. 2023. Transition to turbulence in pipe flow. Annual Review of Fluid Mechanics. 55, 575–602.","chicago":"Avila, Marc, Dwight Barkley, and Björn Hof. “Transition to Turbulence in Pipe Flow.” Annual Review of Fluid Mechanics. Annual Reviews, 2023. https://doi.org/10.1146/annurev-fluid-120720-025957."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","external_id":{"isi":["000915418100023"]},"article_processing_charge":"No","author":[{"last_name":"Avila","full_name":"Avila, Marc","first_name":"Marc"},{"first_name":"Dwight","last_name":"Barkley","full_name":"Barkley, Dwight"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof"}],"title":"Transition to turbulence in pipe flow","project":[{"_id":"238598C6-32DE-11EA-91FC-C7463DDC885E","grant_number":"662960","name":"Revisiting the Turbulence Problem Using Statistical Mechanics: Experimental Studies on Transitional and Turbulent Flows"}]},{"language":[{"iso":"eng"}],"publication_status":"published","publication_identifier":{"issn":["2214-7853"]},"volume":78,"issue":"Part 1","oa_version":"None","abstract":[{"text":"In industrial reactors and equipment, non-ideality is quite a common phenomenon rather than an exception. These deviations from ideality impact the process's overall efficiency and the effectiveness of the equipment. To recognize the associated non-ideality, one needs to have enough understanding of the formulation of the equations and in-depth knowledge of the residence time distribution (RTD) data of real reactors. In the current work, step input and pulse input were used to create RTD data for Cascade continuous stirred tank reactors (CSTRs). For the aforementioned configuration, experiments were run at various flow rates to validate the developed characteristic equations. To produce RTD data, distilled water was utilized as the flowing fluid, and NaOH was the tracer substance. The ideal behavior of tracer concentration exits age distribution, and cumulative fraction for each setup and each input was plotted and experimental results were compared with perfect behavior. Deviation of concentration exit age distribution and cumulative fractional distribution from ideal behavior is more in pulse input as compared to a step input. For ideal cases, the exit age distribution curve and cumulative fraction curves are independent of the type of input. But a significant difference was observed for the two cases, which may be due to non-measurable fluctuations in volumetric flow rate, non-achievement of instant injection of tracer in case of pulse input, and slight variations in the sampling period. Further, with increasing flow rate, concentration, exit age, and cumulative fractional curves shifted upward, and this behavior matches with the actual case.","lang":"eng"}],"intvolume":" 78","month":"03","scopus_import":"1","date_updated":"2023-08-16T09:08:11Z","department":[{"_id":"BjHo"}],"_id":"12172","keyword":["General Medicine"],"status":"public","article_type":"original","type":"journal_article","publication":"Materials Today: Proceedings","day":"20","year":"2023","date_created":"2023-01-12T12:11:26Z","doi":"10.1016/j.matpr.2022.11.037","date_published":"2023-03-20T00:00:00Z","page":"40-47","publisher":"Elsevier","quality_controlled":"1","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"ama":"Khatoon B, Kamil S, Babu H, Siraj Alam M. Experimental analysis of Cascade CSTRs with step and pulse inputs. Materials Today: Proceedings. 2023;78(Part 1):40-47. doi:10.1016/j.matpr.2022.11.037","apa":"Khatoon, B., Kamil, S., Babu, H., & Siraj Alam, M. (2023). Experimental analysis of Cascade CSTRs with step and pulse inputs. Materials Today: Proceedings. Elsevier. https://doi.org/10.1016/j.matpr.2022.11.037","short":"B. Khatoon, S. Kamil, H. Babu, M. Siraj Alam, Materials Today: Proceedings 78 (2023) 40–47.","ieee":"B. Khatoon, S. Kamil, H. Babu, and M. Siraj Alam, “Experimental analysis of Cascade CSTRs with step and pulse inputs,” Materials Today: Proceedings, vol. 78, no. Part 1. Elsevier, pp. 40–47, 2023.","mla":"Khatoon, Bushra, et al. “Experimental Analysis of Cascade CSTRs with Step and Pulse Inputs.” Materials Today: Proceedings, vol. 78, no. Part 1, Elsevier, 2023, pp. 40–47, doi:10.1016/j.matpr.2022.11.037.","ista":"Khatoon B, Kamil S, Babu H, Siraj Alam M. 2023. Experimental analysis of Cascade CSTRs with step and pulse inputs. Materials Today: Proceedings. 78(Part 1), 40–47.","chicago":"Khatoon, Bushra, Shoaib Kamil, Hitesh Babu, and M. Siraj Alam. “Experimental Analysis of Cascade CSTRs with Step and Pulse Inputs.” Materials Today: Proceedings. Elsevier, 2023. https://doi.org/10.1016/j.matpr.2022.11.037."},"title":"Experimental analysis of Cascade CSTRs with step and pulse inputs","article_processing_charge":"No","author":[{"last_name":"Khatoon","full_name":"Khatoon, Bushra","first_name":"Bushra"},{"first_name":"Shoaib","id":"185a19af-dc7d-11ea-9b2f-8eb2201959e9","last_name":"Kamil","full_name":"Kamil, Shoaib"},{"last_name":"Babu","full_name":"Babu, Hitesh","first_name":"Hitesh"},{"first_name":"M.","last_name":"Siraj Alam","full_name":"Siraj Alam, M."}]},{"pmid":1,"oa_version":"None","abstract":[{"lang":"eng","text":"Flows through pipes and channels are, in practice, almost always turbulent, and the multiscale eddying motion is responsible for a major part of the encountered friction losses and pumping costs1. Conversely, for pulsatile flows, in particular for aortic blood flow, turbulence levels remain low despite relatively large peak velocities. For aortic blood flow, high turbulence levels are intolerable as they would damage the shear-sensitive endothelial cell layer2,3,4,5. Here we show that turbulence in ordinary pipe flow is diminished if the flow is driven in a pulsatile mode that incorporates all the key features of the cardiac waveform. At Reynolds numbers comparable to those of aortic blood flow, turbulence is largely inhibited, whereas at much higher speeds, the turbulent drag is reduced by more than 25%. This specific operation mode is more efficient when compared with steady driving, which is the present situation for virtually all fluid transport processes ranging from heating circuits to water, gas and oil pipelines."}],"acknowledged_ssus":[{"_id":"M-Shop"},{"_id":"ScienComp"}],"month":"09","intvolume":" 621","scopus_import":"1","language":[{"iso":"eng"}],"publication_identifier":{"issn":["0028-0836"],"eissn":["1476-4687"]},"publication_status":"published","volume":621,"issue":"7977","related_material":{"link":[{"url":"https://www.ista.ac.at/en/news/pumping-like-the-heart/","relation":"press_release","description":"News on ISTA website"}]},"_id":"14341","status":"public","type":"journal_article","article_type":"original","date_updated":"2023-09-20T12:10:22Z","department":[{"_id":"BjHo"}],"acknowledgement":"We acknowledge the assistance of the Miba machine shop and the team of the ISTA-HPC cluster. We thank M. Quadrio for the discussions. The work was supported by the Simons Foundation (grant no. 662960) and by the Austrian Science Fund (grant no. I4188-N30), within Deutsche Forschungsgemeinschaft research unit FOR 2688.","publisher":"Springer Nature","quality_controlled":"1","day":"07","publication":"Nature","year":"2023","date_published":"2023-09-07T00:00:00Z","doi":"10.1038/s41586-023-06399-5","date_created":"2023-09-17T22:01:09Z","page":"71-74","project":[{"name":"Revisiting the Turbulence Problem Using Statistical Mechanics: Experimental Studies on Transitional and Turbulent Flows","grant_number":"662960","_id":"238598C6-32DE-11EA-91FC-C7463DDC885E"},{"_id":"238B8092-32DE-11EA-91FC-C7463DDC885E","call_identifier":"FWF","grant_number":"I04188","name":"Instabilities in pulsating pipe flow of Newtonian and complex fluids"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"ista":"Scarselli D, Lopez Alonso JM, Varshney A, Hof B. 2023. Turbulence suppression by cardiac-cycle-inspired driving of pipe flow. Nature. 621(7977), 71–74.","chicago":"Scarselli, Davide, Jose M Lopez Alonso, Atul Varshney, and Björn Hof. “Turbulence Suppression by Cardiac-Cycle-Inspired Driving of Pipe Flow.” Nature. Springer Nature, 2023. https://doi.org/10.1038/s41586-023-06399-5.","apa":"Scarselli, D., Lopez Alonso, J. M., Varshney, A., & Hof, B. (2023). Turbulence suppression by cardiac-cycle-inspired driving of pipe flow. Nature. Springer Nature. https://doi.org/10.1038/s41586-023-06399-5","ama":"Scarselli D, Lopez Alonso JM, Varshney A, Hof B. Turbulence suppression by cardiac-cycle-inspired driving of pipe flow. Nature. 2023;621(7977):71-74. doi:10.1038/s41586-023-06399-5","short":"D. Scarselli, J.M. Lopez Alonso, A. Varshney, B. Hof, Nature 621 (2023) 71–74.","ieee":"D. Scarselli, J. M. Lopez Alonso, A. Varshney, and B. Hof, “Turbulence suppression by cardiac-cycle-inspired driving of pipe flow,” Nature, vol. 621, no. 7977. Springer Nature, pp. 71–74, 2023.","mla":"Scarselli, Davide, et al. “Turbulence Suppression by Cardiac-Cycle-Inspired Driving of Pipe Flow.” Nature, vol. 621, no. 7977, Springer Nature, 2023, pp. 71–74, doi:10.1038/s41586-023-06399-5."},"title":"Turbulence suppression by cardiac-cycle-inspired driving of pipe flow","author":[{"id":"40315C30-F248-11E8-B48F-1D18A9856A87","first_name":"Davide","last_name":"Scarselli","orcid":"0000-0001-5227-4271","full_name":"Scarselli, Davide"},{"id":"40770848-F248-11E8-B48F-1D18A9856A87","first_name":"Jose M","full_name":"Lopez Alonso, Jose M","orcid":"0000-0002-0384-2022","last_name":"Lopez Alonso"},{"last_name":"Varshney","orcid":"0000-0002-3072-5999","full_name":"Varshney, Atul","first_name":"Atul","id":"2A2006B2-F248-11E8-B48F-1D18A9856A87"},{"orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof","id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn"}],"article_processing_charge":"No","external_id":{"pmid":["37673988"]}},{"file_date_updated":"2023-11-24T11:57:46Z","department":[{"_id":"GradSch"},{"_id":"BjHo"}],"date_updated":"2023-11-30T10:55:13Z","supervisor":[{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754"}],"ddc":["530"],"type":"dissertation","status":"public","_id":"12726","related_material":{"record":[{"relation":"part_of_dissertation","id":"10703","status":"public"},{"relation":"part_of_dissertation","status":"public","id":"10791"},{"id":"7932","status":"public","relation":"part_of_dissertation"},{"relation":"part_of_dissertation","id":"461","status":"public"},{"relation":"new_edition","status":"public","id":"14530"}]},"publication_status":"published","degree_awarded":"PhD","publication_identifier":{"issn":["2663-337X"]},"language":[{"iso":"eng"}],"file":[{"file_name":"Thesis_Riedl_2023.pdf","date_created":"2023-03-23T12:49:23Z","creator":"cchlebak","file_size":63734746,"date_updated":"2023-11-24T11:57:46Z","checksum":"eba0e19fe57a8c15e7aeab55a845efb7","file_id":"12745","relation":"main_file","access_level":"closed","content_type":"application/pdf","description":"the main file is missing the bibliography. See new thesis record 14530 for updated files."},{"checksum":"0eb7b650cc8ae843bcec7c8a6109ae03","file_id":"12746","relation":"source_file","access_level":"closed","embargo_to":"open_access","content_type":"application/octet-stream","file_name":"Thesis_Riedl_2023_source.rar","date_created":"2023-03-23T12:54:34Z","creator":"cchlebak","file_size":339473651,"date_updated":"2023-09-24T22:30:03Z"}],"alternative_title":["ISTA Thesis"],"month":"03","acknowledged_ssus":[{"_id":"M-Shop"},{"_id":"Bio"}],"abstract":[{"text":"Most motions of many-body systems at any scale in nature with sufficient degrees\r\nof freedom tend to be chaotic; reaching from the orbital motion of planets, the air\r\ncurrents in our atmosphere, down to the water flowing through our pipelines or\r\nthe movement of a population of bacteria. To the observer it is therefore intriguing\r\nwhen a moving collective exhibits order. Collective motion of flocks of birds, schools\r\nof fish or swarms of self-propelled particles or robots have been studied extensively\r\nover the past decades but the mechanisms involved in the transition from chaos to\r\norder remain unclear. Here, the interactions, that in most systems give rise to chaos,\r\nsustain order. In this thesis we investigate mechanisms that preserve, destabilize\r\nor lead to the ordered state. We show that endothelial cells migrating in circular\r\nconfinements transition to a collective rotating state and concomitantly synchronize\r\nthe frequencies of nucleating actin waves within individual cells. Consequently,\r\nthe frequency dependent cell migration speed uniformizes across the population.\r\nComplementary to the WAVE dependent nucleation of traveling actin waves, we\r\nshow that in leukocytes the actin polymerization depending on WASp generates\r\npushing forces locally at stationary patches. Next, in pipe flows, we study methods\r\nto disrupt the self–sustaining cycle of turbulence and therefore relaminarize the\r\nflow. While we find in pulsating flow conditions that turbulence emerges through a\r\nhelical instability during the decelerating phase. Finally, we show quantitatively in\r\nbrain slices of mice that wild-type control neurons can compensate the migratory\r\ndeficits of a genetically modified neuronal sub–population in the developing cortex.","lang":"eng"}],"oa_version":"None","article_processing_charge":"No","author":[{"first_name":"Michael","id":"3BE60946-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0003-4844-6311","full_name":"Riedl, Michael","last_name":"Riedl"}],"title":"Synchronization in collectively moving active matter","citation":{"ista":"Riedl M. 2023. Synchronization in collectively moving active matter. Institute of Science and Technology Austria.","chicago":"Riedl, Michael. “Synchronization in Collectively Moving Active Matter.” Institute of Science and Technology Austria, 2023. https://doi.org/10.15479/at:ista:12726.","short":"M. Riedl, Synchronization in Collectively Moving Active Matter, Institute of Science and Technology Austria, 2023.","ieee":"M. Riedl, “Synchronization in collectively moving active matter,” Institute of Science and Technology Austria, 2023.","apa":"Riedl, M. (2023). Synchronization in collectively moving active matter. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:12726","ama":"Riedl M. Synchronization in collectively moving active matter. 2023. doi:10.15479/at:ista:12726","mla":"Riedl, Michael. Synchronization in Collectively Moving Active Matter. Institute of Science and Technology Austria, 2023, doi:10.15479/at:ista:12726."},"user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","page":"260","date_created":"2023-03-15T13:22:13Z","date_published":"2023-03-23T00:00:00Z","doi":"10.15479/at:ista:12726","year":"2023","has_accepted_license":"1","day":"23","publisher":"Institute of Science and Technology Austria"},{"department":[{"_id":"GradSch"},{"_id":"BjHo"}],"date_updated":"2023-12-13T11:40:19Z","keyword":["General Physics and Astronomy"],"status":"public","type":"journal_article","article_type":"original","_id":"13274","volume":131,"issue":"3","language":[{"iso":"eng"}],"publication_status":"published","publication_identifier":{"eissn":["1079-7114"],"issn":["0031-9007"]},"intvolume":" 131","month":"07","main_file_link":[{"open_access":"1","url":"https://doi.org/10.48550/arXiv.2306.05098"}],"oa_version":"Preprint","abstract":[{"lang":"eng","text":"Viscous flows through pipes and channels are steady and ordered until, with increasing velocity, the laminar motion catastrophically breaks down and gives way to turbulence. How this apparently discontinuous change from low- to high-dimensional motion can be rationalized within the framework of the Navier-Stokes equations is not well understood. Exploiting geometrical properties of transitional channel flow we trace turbulence to far lower Reynolds numbers (Re) than previously possible and identify the complete path that reversibly links fully turbulent motion to an invariant solution. This precursor of turbulence destabilizes rapidly with Re, and the accompanying explosive increase in attractor dimension effectively marks the transition between deterministic and de facto stochastic dynamics."}],"title":"Direct path from turbulence to time-periodic solutions","article_processing_charge":"No","external_id":{"isi":["001052929900004"],"arxiv":["2306.05098"]},"author":[{"id":"3D85B7C4-F248-11E8-B48F-1D18A9856A87","first_name":"Chaitanya S","last_name":"Paranjape","full_name":"Paranjape, Chaitanya S"},{"orcid":"0000-0002-8490-9312","full_name":"Yalniz, Gökhan","last_name":"Yalniz","first_name":"Gökhan","id":"66E74FA2-D8BF-11E9-8249-8DE2E5697425"},{"full_name":"Duguet, Yohann","last_name":"Duguet","first_name":"Yohann"},{"first_name":"Nazmi B","id":"3EA1010E-F248-11E8-B48F-1D18A9856A87","full_name":"Budanur, Nazmi B","orcid":"0000-0003-0423-5010","last_name":"Budanur"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"mla":"Paranjape, Chaitanya S., et al. “Direct Path from Turbulence to Time-Periodic Solutions.” Physical Review Letters, vol. 131, no. 3, 034002, American Physical Society, 2023, doi:10.1103/physrevlett.131.034002.","ama":"Paranjape CS, Yalniz G, Duguet Y, Budanur NB, Hof B. Direct path from turbulence to time-periodic solutions. Physical Review Letters. 2023;131(3). doi:10.1103/physrevlett.131.034002","apa":"Paranjape, C. S., Yalniz, G., Duguet, Y., Budanur, N. B., & Hof, B. (2023). Direct path from turbulence to time-periodic solutions. Physical Review Letters. American Physical Society. https://doi.org/10.1103/physrevlett.131.034002","short":"C.S. Paranjape, G. Yalniz, Y. Duguet, N.B. Budanur, B. Hof, Physical Review Letters 131 (2023).","ieee":"C. S. Paranjape, G. Yalniz, Y. Duguet, N. B. Budanur, and B. Hof, “Direct path from turbulence to time-periodic solutions,” Physical Review Letters, vol. 131, no. 3. American Physical Society, 2023.","chicago":"Paranjape, Chaitanya S, Gökhan Yalniz, Yohann Duguet, Nazmi B Budanur, and Björn Hof. “Direct Path from Turbulence to Time-Periodic Solutions.” Physical Review Letters. American Physical Society, 2023. https://doi.org/10.1103/physrevlett.131.034002.","ista":"Paranjape CS, Yalniz G, Duguet Y, Budanur NB, Hof B. 2023. Direct path from turbulence to time-periodic solutions. Physical Review Letters. 131(3), 034002."},"project":[{"grant_number":"662960","name":"Revisiting the Turbulence Problem Using Statistical Mechanics: Experimental Studies on Transitional and Turbulent Flows","_id":"238598C6-32DE-11EA-91FC-C7463DDC885E"}],"article_number":"034002","date_created":"2023-07-24T09:43:59Z","doi":"10.1103/physrevlett.131.034002","date_published":"2023-07-21T00:00:00Z","publication":"Physical Review Letters","day":"21","year":"2023","isi":1,"oa":1,"publisher":"American Physical Society","quality_controlled":"1","acknowledgement":"We thank Baofang Song as well as the developers of Channelflow for sharing their numerical codes, and Mukund Vasudevan and Holger Kantz for fruitful discussions. This work was supported by a grant from the Simons Foundation (662960, B. H.)."},{"_id":"14361","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"type":"journal_article","article_type":"original","status":"public","date_updated":"2023-12-13T12:29:41Z","ddc":["530","570"],"file_date_updated":"2023-09-25T08:32:37Z","department":[{"_id":"MiSi"},{"_id":"NanoFab"},{"_id":"BjHo"}],"acknowledged_ssus":[{"_id":"Bio"},{"_id":"LifeSc"},{"_id":"M-Shop"}],"abstract":[{"lang":"eng","text":"Whether one considers swarming insects, flocking birds, or bacterial colonies, collective motion arises from the coordination of individuals and entails the adjustment of their respective velocities. In particular, in close confinements, such as those encountered by dense cell populations during development or regeneration, collective migration can only arise coordinately. Yet, how individuals unify their velocities is often not understood. Focusing on a finite number of cells in circular confinements, we identify waves of polymerizing actin that function as a pacemaker governing the speed of individual cells. We show that the onset of collective motion coincides with the synchronization of the wave nucleation frequencies across the population. Employing a simpler and more readily accessible mechanical model system of active spheres, we identify the synchronization of the individuals’ internal oscillators as one of the essential requirements to reach the corresponding collective state. The mechanical ‘toy’ experiment illustrates that the global synchronous state is achieved by nearest neighbor coupling. We suggest by analogy that local coupling and the synchronization of actin waves are essential for the emergent, self-organized motion of cell collectives."}],"pmid":1,"oa_version":"Published Version","scopus_import":"1","intvolume":" 14","month":"09","publication_status":"published","publication_identifier":{"eissn":["2041-1723"]},"language":[{"iso":"eng"}],"file":[{"date_created":"2023-09-25T08:32:37Z","file_name":"2023_NatureComm_Riedl.pdf","creator":"dernst","date_updated":"2023-09-25T08:32:37Z","file_size":2317272,"file_id":"14366","checksum":"82d2d4ad736cc8493db8ce45cd313f7b","success":1,"access_level":"open_access","relation":"main_file","content_type":"application/pdf"}],"ec_funded":1,"volume":14,"article_number":"5633","project":[{"_id":"25A603A2-B435-11E9-9278-68D0E5697425","call_identifier":"FP7","name":"Cytoskeletal force generation and force transduction of migrating leukocytes","grant_number":"281556"},{"call_identifier":"H2020","_id":"25FE9508-B435-11E9-9278-68D0E5697425","grant_number":"724373","name":"Cellular navigation along spatial gradients"}],"citation":{"mla":"Riedl, Michael, et al. “Synchronization in Collectively Moving Inanimate and Living Active Matter.” Nature Communications, vol. 14, 5633, Springer Nature, 2023, doi:10.1038/s41467-023-41432-1.","short":"M. Riedl, I.D. Mayer, J. Merrin, M.K. Sixt, B. Hof, Nature Communications 14 (2023).","ieee":"M. Riedl, I. D. Mayer, J. Merrin, M. K. Sixt, and B. Hof, “Synchronization in collectively moving inanimate and living active matter,” Nature Communications, vol. 14. Springer Nature, 2023.","apa":"Riedl, M., Mayer, I. D., Merrin, J., Sixt, M. K., & Hof, B. (2023). Synchronization in collectively moving inanimate and living active matter. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-023-41432-1","ama":"Riedl M, Mayer ID, Merrin J, Sixt MK, Hof B. Synchronization in collectively moving inanimate and living active matter. Nature Communications. 2023;14. doi:10.1038/s41467-023-41432-1","chicago":"Riedl, Michael, Isabelle D Mayer, Jack Merrin, Michael K Sixt, and Björn Hof. “Synchronization in Collectively Moving Inanimate and Living Active Matter.” Nature Communications. Springer Nature, 2023. https://doi.org/10.1038/s41467-023-41432-1.","ista":"Riedl M, Mayer ID, Merrin J, Sixt MK, Hof B. 2023. Synchronization in collectively moving inanimate and living active matter. Nature Communications. 14, 5633."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","article_processing_charge":"Yes","external_id":{"pmid":["37704595"],"isi":["001087583700030"]},"author":[{"last_name":"Riedl","orcid":"0000-0003-4844-6311","full_name":"Riedl, Michael","first_name":"Michael","id":"3BE60946-F248-11E8-B48F-1D18A9856A87"},{"full_name":"Mayer, Isabelle D","last_name":"Mayer","first_name":"Isabelle D","id":"61763940-15b2-11ec-abd3-cfaddfbc66b4"},{"orcid":"0000-0001-5145-4609","full_name":"Merrin, Jack","last_name":"Merrin","id":"4515C308-F248-11E8-B48F-1D18A9856A87","first_name":"Jack"},{"last_name":"Sixt","orcid":"0000-0002-6620-9179","full_name":"Sixt, Michael K","first_name":"Michael K","id":"41E9FBEA-F248-11E8-B48F-1D18A9856A87"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof"}],"title":"Synchronization in collectively moving inanimate and living active matter","acknowledgement":"We thank K. O’Keeffe, E. Hannezo, P. Devreotes, C. Dessalles, and E. Martens for discussion and/or critical reading of the manuscript; the Bioimaging Facility of ISTA for excellent support, as well as the Life Science Facility and the Miba Machine Shop of ISTA. This work was supported by the European Research Council (ERC StG 281556 and CoG 724373) to M.S.","oa":1,"publisher":"Springer Nature","quality_controlled":"1","year":"2023","has_accepted_license":"1","isi":1,"publication":"Nature Communications","day":"13","date_created":"2023-09-24T22:01:10Z","date_published":"2023-09-13T00:00:00Z","doi":"10.1038/s41467-023-41432-1"},{"article_number":"0112","author":[{"full_name":"Wang, B.","last_name":"Wang","first_name":"B."},{"full_name":"Mellibovsky, F.","last_name":"Mellibovsky","first_name":"F."},{"orcid":"0000-0001-6572-0621","full_name":"Ayats López, Roger","last_name":"Ayats López","first_name":"Roger","id":"ab77522d-073b-11ed-8aff-e71b39258362"},{"full_name":"Deguchi, K.","last_name":"Deguchi","first_name":"K."},{"first_name":"A.","full_name":"Meseguer, A.","last_name":"Meseguer"}],"external_id":{"pmid":["36907214"]},"article_processing_charge":"No","title":"Mean structure of the supercritical turbulent spiral in Taylor–Couette flow","citation":{"ieee":"B. Wang, F. Mellibovsky, R. Ayats López, K. Deguchi, and A. Meseguer, “Mean structure of the supercritical turbulent spiral in Taylor–Couette flow,” Philosophical Transactions of the Royal Society A, vol. 381, no. 2246. The Royal Society, 2023.","short":"B. Wang, F. Mellibovsky, R. Ayats López, K. Deguchi, A. Meseguer, Philosophical Transactions of the Royal Society A 381 (2023).","ama":"Wang B, Mellibovsky F, Ayats López R, Deguchi K, Meseguer A. Mean structure of the supercritical turbulent spiral in Taylor–Couette flow. Philosophical Transactions of the Royal Society A. 2023;381(2246). doi:10.1098/rsta.2022.0112","apa":"Wang, B., Mellibovsky, F., Ayats López, R., Deguchi, K., & Meseguer, A. (2023). Mean structure of the supercritical turbulent spiral in Taylor–Couette flow. Philosophical Transactions of the Royal Society A. The Royal Society. https://doi.org/10.1098/rsta.2022.0112","mla":"Wang, B., et al. “Mean Structure of the Supercritical Turbulent Spiral in Taylor–Couette Flow.” Philosophical Transactions of the Royal Society A, vol. 381, no. 2246, 0112, The Royal Society, 2023, doi:10.1098/rsta.2022.0112.","ista":"Wang B, Mellibovsky F, Ayats López R, Deguchi K, Meseguer A. 2023. Mean structure of the supercritical turbulent spiral in Taylor–Couette flow. Philosophical Transactions of the Royal Society A. 381(2246), 0112.","chicago":"Wang, B., F. Mellibovsky, Roger Ayats López, K. Deguchi, and A. Meseguer. “Mean Structure of the Supercritical Turbulent Spiral in Taylor–Couette Flow.” Philosophical Transactions of the Royal Society A. The Royal Society, 2023. https://doi.org/10.1098/rsta.2022.0112."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","publisher":"The Royal Society","quality_controlled":"1","oa":1,"acknowledgement":"K.D.’s research was supported by Australian Research Council Discovery Early Career Researcher Award (DE170100171). B.W., R.A., F.M. and A.M. research was supported by the Spanish Ministerio de Economía y Competitividad (grant nos. FIS2016-77849-R and FIS2017-85794-P) and Ministerio de Ciencia e Innovación (grant no. PID2020-114043GB-I00) and the Generalitat de Catalunya (grant no. 2017-SGR-785). B.W.’s research was also supported by the Chinese Scholarship Council (grant CSC no. 201806440152). F.M. is a Serra-Húnter Fellow.","date_published":"2023-05-01T00:00:00Z","doi":"10.1098/rsta.2022.0112","date_created":"2024-01-08T13:11:45Z","has_accepted_license":"1","year":"2023","day":"01","publication":"Philosophical Transactions of the Royal Society A","article_type":"original","type":"journal_article","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"status":"public","keyword":["General Physics and Astronomy","General Engineering","General Mathematics"],"_id":"14754","department":[{"_id":"BjHo"}],"file_date_updated":"2024-01-09T09:13:53Z","date_updated":"2024-01-09T09:15:29Z","ddc":["530"],"scopus_import":"1","month":"05","intvolume":" 381","abstract":[{"lang":"eng","text":"The large-scale laminar/turbulent spiral patterns that appear in the linearly unstable regime of counter-rotating Taylor–Couette flow are investigated from a statistical perspective by means of direct numerical simulation. Unlike the vast majority of previous numerical studies, we analyse the flow in periodic parallelogram-annular domains, following a coordinate change that aligns one of the parallelogram sides with the spiral pattern. The domain size, shape and spatial resolution have been varied and the results compared with those in a sufficiently large computational orthogonal domain with natural axial and azimuthal periodicity. We find that a minimal parallelogram of the right tilt significantly reduces the computational cost without notably compromising the statistical properties of the supercritical turbulent spiral. Its mean structure, obtained from extremely long time integrations in a co-rotating reference frame using the method of slices, bears remarkable similarity with the turbulent stripes observed in plane Couette flow, the centrifugal instability playing only a secondary role."}],"pmid":1,"oa_version":"Submitted Version","volume":381,"issue":"2246","publication_identifier":{"eissn":["1471-2962"],"issn":["1364-503X"]},"publication_status":"published","file":[{"content_type":"application/pdf","relation":"main_file","access_level":"open_access","success":1,"file_id":"14763","checksum":"1978d126c0ce2f47c22ac20107cc0106","file_size":6421086,"date_updated":"2024-01-09T09:13:53Z","creator":"dernst","file_name":"2023_PhilTransactionsA_Wang_accepted.pdf","date_created":"2024-01-09T09:13:53Z"}],"language":[{"iso":"eng"}]},{"oa_version":"Published Version","abstract":[{"lang":"eng","text":"The first long-lived turbulent structures observable in planar shear flows take the form of localized stripes, inclined with respect to the mean flow direction. The dynamics of these stripes is central to transition, and recent studies proposed an analogy to directed percolation where the stripes’ proliferation is ultimately responsible for the turbulence becoming sustained. In the present study we focus on the internal stripe dynamics as well as on the eventual stripe expansion, and we compare the underlying mechanisms in pressure- and shear-driven planar flows, respectively, plane-Poiseuille and plane-Couette flow. Despite the similarities of the overall laminar–turbulence patterns, the stripe proliferation processes in the two cases are fundamentally different. Starting from the growth and sustenance of individual stripes, we find that in plane-Couette flow new streaks are created stochastically throughout the stripe whereas in plane-Poiseuille flow streak creation is deterministic and occurs locally at the downstream tip. Because of the up/downstream symmetry, Couette stripes, in contrast to Poiseuille stripes, have two weak and two strong laminar turbulent interfaces. These differences in symmetry as well as in internal growth give rise to two fundamentally different stripe splitting mechanisms. In plane-Poiseuille flow splitting is connected to the elongational growth of the original stripe, and it results from a break-off/shedding of the stripe's tail. In plane-Couette flow splitting follows from a broadening of the original stripe and a division along the stripe into two slimmer stripes."}],"month":"11","intvolume":" 974","file":[{"creator":"dernst","file_size":2804641,"date_updated":"2024-02-15T09:05:21Z","file_name":"2023_JourFluidMechanics_Marensi.pdf","date_created":"2024-02-15T09:05:21Z","relation":"main_file","access_level":"open_access","content_type":"application/pdf","success":1,"file_id":"14996","checksum":"17c64c1fb0d5f73252364bf98b0b9e1a"}],"language":[{"iso":"eng"}],"publication_identifier":{"issn":["0022-1120"],"eissn":["1469-7645"]},"publication_status":"published","volume":974,"_id":"14466","status":"public","keyword":["turbulence","transition to turbulence","patterns"],"type":"journal_article","article_type":"original","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"ddc":["530"],"date_updated":"2024-02-15T09:06:23Z","department":[{"_id":"GradSch"},{"_id":"BjHo"}],"file_date_updated":"2024-02-15T09:05:21Z","acknowledgement":"E.M. acknowledges funding from the ISTplus fellowship programme. G.Y. and B.H. acknowledge a grant from the Simons Foundation (662960, BH).","quality_controlled":"1","publisher":"Cambridge University Press","oa":1,"day":"10","publication":"Journal of Fluid Mechanics","has_accepted_license":"1","isi":1,"year":"2023","date_published":"2023-11-10T00:00:00Z","doi":"10.1017/jfm.2023.780","date_created":"2023-10-30T09:32:28Z","article_number":"A21","project":[{"_id":"238598C6-32DE-11EA-91FC-C7463DDC885E","grant_number":"662960","name":"Revisiting the Turbulence Problem Using Statistical Mechanics: Experimental Studies on Transitional and Turbulent Flows"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"ama":"Marensi E, Yalniz G, Hof B. Dynamics and proliferation of turbulent stripes in plane-Poiseuille and plane-Couette flows. Journal of Fluid Mechanics. 2023;974. doi:10.1017/jfm.2023.780","apa":"Marensi, E., Yalniz, G., & Hof, B. (2023). Dynamics and proliferation of turbulent stripes in plane-Poiseuille and plane-Couette flows. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2023.780","short":"E. Marensi, G. Yalniz, B. Hof, Journal of Fluid Mechanics 974 (2023).","ieee":"E. Marensi, G. Yalniz, and B. Hof, “Dynamics and proliferation of turbulent stripes in plane-Poiseuille and plane-Couette flows,” Journal of Fluid Mechanics, vol. 974. Cambridge University Press, 2023.","mla":"Marensi, Elena, et al. “Dynamics and Proliferation of Turbulent Stripes in Plane-Poiseuille and Plane-Couette Flows.” Journal of Fluid Mechanics, vol. 974, A21, Cambridge University Press, 2023, doi:10.1017/jfm.2023.780.","ista":"Marensi E, Yalniz G, Hof B. 2023. Dynamics and proliferation of turbulent stripes in plane-Poiseuille and plane-Couette flows. Journal of Fluid Mechanics. 974, A21.","chicago":"Marensi, Elena, Gökhan Yalniz, and Björn Hof. “Dynamics and Proliferation of Turbulent Stripes in Plane-Poiseuille and Plane-Couette Flows.” Journal of Fluid Mechanics. Cambridge University Press, 2023. https://doi.org/10.1017/jfm.2023.780."},"title":"Dynamics and proliferation of turbulent stripes in plane-Poiseuille and plane-Couette flows","author":[{"last_name":"Marensi","orcid":"0000-0001-7173-4923","full_name":"Marensi, Elena","id":"0BE7553A-1004-11EA-B805-18983DDC885E","first_name":"Elena"},{"last_name":"Yalniz","full_name":"Yalniz, Gökhan","orcid":"0000-0002-8490-9312","id":"66E74FA2-D8BF-11E9-8249-8DE2E5697425","first_name":"Gökhan"},{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof"}],"article_processing_charge":"Yes (via OA deal)","external_id":{"arxiv":["2212.12406"],"isi":["001088363700001"]}},{"ec_funded":1,"publication_identifier":{"issn":["2663 - 337X"]},"publication_status":"published","degree_awarded":"PhD","file":[{"date_updated":"2023-12-06T13:13:26Z","file_size":46405919,"creator":"mhenness","date_created":"2023-12-06T13:13:26Z","file_name":"mike_thesis_v06-12-2023.odt","content_type":"application/vnd.oasis.opendocument.text","access_level":"closed","relation":"source_file","checksum":"4127c285b34f4bf7fb31ef24f9d14c25","file_id":"14648"},{"creator":"mhenness","file_size":21282155,"date_updated":"2023-12-06T13:14:15Z","file_name":"mike_thesis_v06-12-2023.pdf","date_created":"2023-12-06T13:14:15Z","relation":"main_file","access_level":"closed","embargo_to":"open_access","content_type":"application/pdf","embargo":"2024-11-30","file_id":"14649","checksum":"f5203a61eddaf35235bbc51904d73982"},{"access_level":"closed","relation":"other","content_type":"application/pdf","file_id":"15145","checksum":"9f7b4d646f1cfb57e3b9106a8a9cdd9d","creator":"cchlebak","date_updated":"2024-03-20T13:19:36Z","file_size":2930287,"date_created":"2024-03-20T13:19:36Z","file_name":"2023_Hennessey_Michael_Thesis_from_source.pdf"}],"language":[{"iso":"eng"}],"alternative_title":["ISTA Thesis"],"month":"11","acknowledged_ssus":[{"_id":"LifeSc"},{"_id":"Bio"},{"_id":"CampIT"}],"oa_version":"Published Version","department":[{"_id":"GradSch"},{"_id":"BjHo"}],"file_date_updated":"2024-03-20T13:19:36Z","supervisor":[{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof"}],"date_updated":"2024-03-22T13:21:17Z","ddc":["570"],"type":"dissertation","status":"public","keyword":["microfluidics","miceobiology","mutations","quorum sensing"],"_id":"14641","page":"104","doi":"10.15479/at:ista:14641","date_published":"2023-11-30T00:00:00Z","date_created":"2023-12-04T13:17:37Z","has_accepted_license":"1","year":"2023","day":"30","publisher":"Institute of Science and Technology Austria","author":[{"full_name":"Hennessey-Wesen, Mike","last_name":"Hennessey-Wesen","first_name":"Mike","id":"3F338C72-F248-11E8-B48F-1D18A9856A87"}],"article_processing_charge":"No","title":"Adaptive mutation in E. coli modulated by luxS","citation":{"apa":"Hennessey-Wesen, M. (2023). Adaptive mutation in E. coli modulated by luxS. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:14641","ama":"Hennessey-Wesen M. Adaptive mutation in E. coli modulated by luxS. 2023. doi:10.15479/at:ista:14641","ieee":"M. Hennessey-Wesen, “Adaptive mutation in E. coli modulated by luxS,” Institute of Science and Technology Austria, 2023.","short":"M. Hennessey-Wesen, Adaptive Mutation in E. Coli Modulated by LuxS, Institute of Science and Technology Austria, 2023.","mla":"Hennessey-Wesen, Mike. Adaptive Mutation in E. Coli Modulated by LuxS. Institute of Science and Technology Austria, 2023, doi:10.15479/at:ista:14641.","ista":"Hennessey-Wesen M. 2023. Adaptive mutation in E. coli modulated by luxS. Institute of Science and Technology Austria.","chicago":"Hennessey-Wesen, Mike. “Adaptive Mutation in E. Coli Modulated by LuxS.” Institute of Science and Technology Austria, 2023. https://doi.org/10.15479/at:ista:14641."},"user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","project":[{"name":"International IST Doctoral Program","grant_number":"665385","call_identifier":"H2020","_id":"2564DBCA-B435-11E9-9278-68D0E5697425"}]},{"oa_version":"Published Version","abstract":[{"lang":"eng","text":"Standard epidemic models exhibit one continuous, second order phase transition to macroscopic outbreaks. However, interventions to control outbreaks may fundamentally alter epidemic dynamics. Here we reveal how such interventions modify the type of phase transition. In particular, we uncover three distinct types of explosive phase transitions for epidemic dynamics with capacity-limited interventions. Depending on the capacity limit, interventions may (i) leave the standard second order phase transition unchanged but exponentially suppress the probability of large outbreaks, (ii) induce a first-order discontinuous transition to macroscopic outbreaks, or (iii) cause a secondary explosive yet continuous third-order transition. These insights highlight inherent limitations in predicting and containing epidemic outbreaks. More generally our study offers a cornerstone example of a third-order explosive phase transition in complex systems."}],"month":"10","intvolume":" 3","scopus_import":"1","file":[{"creator":"dernst","file_size":1006106,"date_updated":"2023-01-24T07:24:37Z","file_name":"2022_JourPhysics_Boerner.pdf","date_created":"2023-01-24T07:24:37Z","relation":"main_file","access_level":"open_access","content_type":"application/pdf","success":1,"file_id":"12350","checksum":"35c5c5cb0eb17ea1b5184755daab9fc9"}],"language":[{"iso":"eng"}],"publication_identifier":{"issn":["2632-072X"]},"publication_status":"published","volume":3,"issue":"4","_id":"12134","status":"public","keyword":["Artificial Intelligence","Computer Networks and Communications","Computer Science Applications","Information Systems"],"type":"journal_article","article_type":"original","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"ddc":["530"],"date_updated":"2023-02-13T09:15:13Z","file_date_updated":"2023-01-24T07:24:37Z","department":[{"_id":"BjHo"}],"acknowledgement":"We acknowledge support from the Volkswagen Foundation under Grant No. 99720 and the German Federal Ministry for Education and Research (BMBF) under Grant No. 16ICR01. This research was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy—EXC-2068—390729961—Cluster of Excellence Physics of Life of TU Dresden.","publisher":"IOP Publishing","quality_controlled":"1","oa":1,"day":"25","publication":"Journal of Physics: Complexity","has_accepted_license":"1","year":"2022","date_published":"2022-10-25T00:00:00Z","doi":"10.1088/2632-072x/ac99cd","date_created":"2023-01-12T12:03:43Z","article_number":"04LT02","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"ama":"Börner G, Schröder M, Scarselli D, Budanur NB, Hof B, Timme M. Explosive transitions in epidemic dynamics. Journal of Physics: Complexity. 2022;3(4). doi:10.1088/2632-072x/ac99cd","apa":"Börner, G., Schröder, M., Scarselli, D., Budanur, N. B., Hof, B., & Timme, M. (2022). Explosive transitions in epidemic dynamics. Journal of Physics: Complexity. IOP Publishing. https://doi.org/10.1088/2632-072x/ac99cd","ieee":"G. Börner, M. Schröder, D. Scarselli, N. B. Budanur, B. Hof, and M. Timme, “Explosive transitions in epidemic dynamics,” Journal of Physics: Complexity, vol. 3, no. 4. IOP Publishing, 2022.","short":"G. Börner, M. Schröder, D. Scarselli, N.B. Budanur, B. Hof, M. Timme, Journal of Physics: Complexity 3 (2022).","mla":"Börner, Georg, et al. “Explosive Transitions in Epidemic Dynamics.” Journal of Physics: Complexity, vol. 3, no. 4, 04LT02, IOP Publishing, 2022, doi:10.1088/2632-072x/ac99cd.","ista":"Börner G, Schröder M, Scarselli D, Budanur NB, Hof B, Timme M. 2022. Explosive transitions in epidemic dynamics. Journal of Physics: Complexity. 3(4), 04LT02.","chicago":"Börner, Georg, Malte Schröder, Davide Scarselli, Nazmi B Budanur, Björn Hof, and Marc Timme. “Explosive Transitions in Epidemic Dynamics.” Journal of Physics: Complexity. IOP Publishing, 2022. https://doi.org/10.1088/2632-072x/ac99cd."},"title":"Explosive transitions in epidemic dynamics","author":[{"first_name":"Georg","last_name":"Börner","full_name":"Börner, Georg"},{"first_name":"Malte","full_name":"Schröder, Malte","last_name":"Schröder"},{"full_name":"Scarselli, Davide","orcid":"0000-0001-5227-4271","last_name":"Scarselli","first_name":"Davide","id":"40315C30-F248-11E8-B48F-1D18A9856A87"},{"full_name":"Budanur, Nazmi B","orcid":"0000-0003-0423-5010","last_name":"Budanur","first_name":"Nazmi B","id":"3EA1010E-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754"},{"first_name":"Marc","last_name":"Timme","full_name":"Timme, Marc"}],"article_processing_charge":"No"},{"publisher":"American Physical Society","quality_controlled":"1","oa":1,"acknowledgement":"We thank T.Menner, T.Asenov, P. Maier and the Miba machine shop of IST Austria for their valuable support in all technical aspects. We thank Marc Avila for comments on the manuscript. This work was supported by a grant from the Simons Foundation (662960, B.H.). We acknowledge the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement 306589 for financial support. K.A.\r\nacknowledges funding from the Central Research Development Fund of the University of Bremen, grant number ZF04B /2019/FB04 Avila Kerstin (”Independent Project for Postdocs”). L.K. was supported by the European Union’s Horizon 2020 Research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 754411.\r\n","date_published":"2022-01-05T00:00:00Z","doi":"10.1103/PhysRevLett.128.014502","date_created":"2022-01-23T23:01:28Z","day":"05","publication":"Physical Review Letters","isi":1,"year":"2022","project":[{"_id":"260C2330-B435-11E9-9278-68D0E5697425","call_identifier":"H2020","name":"ISTplus - Postdoctoral Fellowships","grant_number":"754411"},{"name":"Decoding the complexity of turbulence at its origin","grant_number":"306589","_id":"25152F3A-B435-11E9-9278-68D0E5697425","call_identifier":"FP7"},{"grant_number":"662960","name":"Revisiting the Turbulence Problem Using Statistical Mechanics: Experimental Studies on Transitional and Turbulent Flows","_id":"238598C6-32DE-11EA-91FC-C7463DDC885E"}],"article_number":"014502","title":"Phase transition to turbulence in spatially extended shear flows","author":[{"last_name":"Klotz","orcid":"0000-0003-1740-7635","full_name":"Klotz, Lukasz","first_name":"Lukasz","id":"2C9AF1C2-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Lemoult","full_name":"Lemoult, Grégoire M","id":"4787FE80-F248-11E8-B48F-1D18A9856A87","first_name":"Grégoire M"},{"last_name":"Avila","full_name":"Avila, Kerstin","first_name":"Kerstin"},{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof"}],"external_id":{"pmid":["35061458"],"isi":["000748271700010"],"arxiv":["2111.14894"]},"article_processing_charge":"No","user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"mla":"Klotz, Lukasz, et al. “Phase Transition to Turbulence in Spatially Extended Shear Flows.” Physical Review Letters, vol. 128, no. 1, 014502, American Physical Society, 2022, doi:10.1103/PhysRevLett.128.014502.","ama":"Klotz L, Lemoult GM, Avila K, Hof B. Phase transition to turbulence in spatially extended shear flows. Physical Review Letters. 2022;128(1). doi:10.1103/PhysRevLett.128.014502","apa":"Klotz, L., Lemoult, G. M., Avila, K., & Hof, B. (2022). Phase transition to turbulence in spatially extended shear flows. Physical Review Letters. American Physical Society. https://doi.org/10.1103/PhysRevLett.128.014502","short":"L. Klotz, G.M. Lemoult, K. Avila, B. Hof, Physical Review Letters 128 (2022).","ieee":"L. Klotz, G. M. Lemoult, K. Avila, and B. Hof, “Phase transition to turbulence in spatially extended shear flows,” Physical Review Letters, vol. 128, no. 1. American Physical Society, 2022.","chicago":"Klotz, Lukasz, Grégoire M Lemoult, Kerstin Avila, and Björn Hof. “Phase Transition to Turbulence in Spatially Extended Shear Flows.” Physical Review Letters. American Physical Society, 2022. https://doi.org/10.1103/PhysRevLett.128.014502.","ista":"Klotz L, Lemoult GM, Avila K, Hof B. 2022. Phase transition to turbulence in spatially extended shear flows. Physical Review Letters. 128(1), 014502."},"month":"01","intvolume":" 128","scopus_import":"1","main_file_link":[{"url":"https://arxiv.org/abs/2111.14894","open_access":"1"}],"pmid":1,"oa_version":"Preprint","abstract":[{"text":"Directed percolation (DP) has recently emerged as a possible solution to the century old puzzle surrounding the transition to turbulence. Multiple model studies reported DP exponents, however, experimental evidence is limited since the largest possible observation times are orders of magnitude shorter than the flows’ characteristic timescales. An exception is cylindrical Couette flow where the limit is not temporal, but rather the realizable system size. We present experiments in a Couette setup of unprecedented azimuthal and axial aspect ratios. Approaching the critical point to within less than 0.1% we determine five critical exponents, all of which are in excellent agreement with the 2+1D DP universality class. The complex dynamics encountered at \r\nthe onset of turbulence can hence be fully rationalized within the framework of statistical mechanics.","lang":"eng"}],"acknowledged_ssus":[{"_id":"M-Shop"}],"volume":128,"issue":"1","ec_funded":1,"language":[{"iso":"eng"}],"publication_identifier":{"issn":["0031-9007"],"eissn":["1079-7114"]},"publication_status":"published","status":"public","type":"journal_article","article_type":"original","_id":"10654","department":[{"_id":"BjHo"}],"date_updated":"2023-08-02T13:59:19Z"},{"article_number":"e0269975","citation":{"mla":"Budanur, Nazmi B., and Björn Hof. “An Autonomous Compartmental Model for Accelerating Epidemics.” PLoS ONE, vol. 17, no. 7, e0269975, Public Library of Science, 2022, doi:10.1371/journal.pone.0269975.","ama":"Budanur NB, Hof B. An autonomous compartmental model for accelerating epidemics. PLoS ONE. 2022;17(7). doi:10.1371/journal.pone.0269975","apa":"Budanur, N. B., & Hof, B. (2022). An autonomous compartmental model for accelerating epidemics. PLoS ONE. Public Library of Science. https://doi.org/10.1371/journal.pone.0269975","ieee":"N. B. Budanur and B. Hof, “An autonomous compartmental model for accelerating epidemics,” PLoS ONE, vol. 17, no. 7. Public Library of Science, 2022.","short":"N.B. Budanur, B. Hof, PLoS ONE 17 (2022).","chicago":"Budanur, Nazmi B, and Björn Hof. “An Autonomous Compartmental Model for Accelerating Epidemics.” PLoS ONE. Public Library of Science, 2022. https://doi.org/10.1371/journal.pone.0269975.","ista":"Budanur NB, Hof B. 2022. An autonomous compartmental model for accelerating epidemics. PLoS ONE. 17(7), e0269975."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","article_processing_charge":"No","external_id":{"isi":["000911392100055"]},"author":[{"id":"3EA1010E-F248-11E8-B48F-1D18A9856A87","first_name":"Nazmi B","last_name":"Budanur","orcid":"0000-0003-0423-5010","full_name":"Budanur, Nazmi B"},{"last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn"}],"title":"An autonomous compartmental model for accelerating epidemics","oa":1,"quality_controlled":"1","publisher":"Public Library of Science","year":"2022","has_accepted_license":"1","isi":1,"publication":"PLoS ONE","day":"18","date_created":"2022-07-31T22:01:48Z","doi":"10.1371/journal.pone.0269975","date_published":"2022-07-18T00:00:00Z","_id":"11704","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"type":"journal_article","article_type":"original","status":"public","date_updated":"2023-08-03T12:24:22Z","ddc":["510"],"file_date_updated":"2022-08-01T08:02:38Z","department":[{"_id":"BjHo"}],"abstract":[{"lang":"eng","text":"In Fall 2020, several European countries reported rapid increases in COVID-19 cases along with growing estimates of the effective reproduction rates. Such an acceleration in epidemic spread is usually attributed to time-dependent effects, e.g. human travel, seasonal behavioral changes, mutations of the pathogen etc. In this case however the acceleration occurred when counter measures such as testing and contact tracing exceeded their capacity limit. Considering Austria as an example, here we show that this dynamics can be captured by a time-independent, i.e. autonomous, compartmental model that incorporates these capacity limits. In this model, the epidemic acceleration coincides with the exhaustion of mitigation efforts, resulting in an increasing fraction of undetected cases that drive the effective reproduction rate progressively higher. We demonstrate that standard models which does not include this effect necessarily result in a systematic underestimation of the effective reproduction rate."}],"oa_version":"Published Version","scopus_import":"1","intvolume":" 17","month":"07","publication_status":"published","publication_identifier":{"eissn":["1932-6203"]},"language":[{"iso":"eng"}],"file":[{"creator":"dernst","date_updated":"2022-08-01T08:02:38Z","file_size":1421256,"date_created":"2022-08-01T08:02:38Z","file_name":"2022_PLoSONE_Budanur.pdf","access_level":"open_access","relation":"main_file","content_type":"application/pdf","checksum":"1ddd9b91e6dec31ab0e7a8433ca2d452","file_id":"11712","success":1}],"related_material":{"record":[{"relation":"research_data","status":"public","id":"11711"}]},"volume":17,"issue":"7"},{"year":"2022","has_accepted_license":"1","day":"06","date_created":"2022-08-01T08:06:33Z","license":"https://creativecommons.org/publicdomain/zero/1.0/","doi":"10.5281/ZENODO.6802720","related_material":{"record":[{"relation":"used_in_publication","status":"public","id":"11704"}]},"date_published":"2022-07-06T00:00:00Z","abstract":[{"text":"Codes and data for reproducing the results of N. B. Budanur and B. Hof \"An autonomous compartmental model for accelerating epidemics\"","lang":"eng"}],"oa_version":"Published Version","main_file_link":[{"open_access":"1","url":"https://doi.org/10.5281/ZENODO.6802720"}],"oa":1,"publisher":"Zenodo","month":"07","date_updated":"2023-08-03T12:24:21Z","citation":{"mla":"Budanur, Nazmi B. Burakbudanur/Autoacc-Public. Zenodo, 2022, doi:10.5281/ZENODO.6802720.","ama":"Budanur NB. burakbudanur/autoacc-public. 2022. doi:10.5281/ZENODO.6802720","apa":"Budanur, N. B. (2022). burakbudanur/autoacc-public. Zenodo. https://doi.org/10.5281/ZENODO.6802720","short":"N.B. Budanur, (2022).","ieee":"N. B. Budanur, “burakbudanur/autoacc-public.” Zenodo, 2022.","chicago":"Budanur, Nazmi B. “Burakbudanur/Autoacc-Public.” Zenodo, 2022. https://doi.org/10.5281/ZENODO.6802720.","ista":"Budanur NB. 2022. burakbudanur/autoacc-public, Zenodo, 10.5281/ZENODO.6802720."},"ddc":["000"],"user_id":"6785fbc1-c503-11eb-8a32-93094b40e1cf","article_processing_charge":"No","author":[{"full_name":"Budanur, Nazmi B","orcid":"0000-0003-0423-5010","last_name":"Budanur","first_name":"Nazmi B","id":"3EA1010E-F248-11E8-B48F-1D18A9856A87"}],"title":"burakbudanur/autoacc-public","department":[{"_id":"BjHo"}],"_id":"11711","tmp":{"image":"/images/cc_0.png","legal_code_url":"https://creativecommons.org/publicdomain/zero/1.0/legalcode","name":"Creative Commons Public Domain Dedication (CC0 1.0)","short":"CC0 (1.0)"},"type":"research_data_reference","status":"public"},{"edition":"1","quality_controlled":"1","publisher":"Springer Nature","acknowledgement":"The work is supported by the National Key Research and Development Program of China (No. 2016YFA0401200), the National Natural Science Foundation of China (Grant Nos. 91952202 and 11402167).","date_created":"2022-03-04T09:14:34Z","doi":"10.1007/978-3-030-67902-6_51","date_published":"2022-01-01T00:00:00Z","page":"587-598","publication":"IUTAM Laminar-Turbulent Transition","day":"01","year":"2022","isi":1,"editor":[{"last_name":"Sherwin","full_name":"Sherwin, Spencer","first_name":"Spencer"},{"last_name":"Schmid","full_name":"Schmid, Peter","first_name":"Peter"},{"first_name":"Xuesong","full_name":"Wu, Xuesong","last_name":"Wu"}],"title":"Effects of streaky structures on the instability of supersonic boundary layers","article_processing_charge":"No","external_id":{"isi":["000709087600051"]},"author":[{"full_name":"Liu, Jianxin","last_name":"Liu","first_name":"Jianxin"},{"first_name":"Elena","id":"0BE7553A-1004-11EA-B805-18983DDC885E","full_name":"Marensi, Elena","last_name":"Marensi"},{"first_name":"Xuesong","last_name":"Wu","full_name":"Wu, Xuesong"}],"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"ama":"Liu J, Marensi E, Wu X. Effects of streaky structures on the instability of supersonic boundary layers. In: Sherwin S, Schmid P, Wu X, eds. IUTAM Laminar-Turbulent Transition. Vol 38. 1st ed. IUTAM Bookseries. Cham: Springer Nature; 2022:587-598. doi:10.1007/978-3-030-67902-6_51","apa":"Liu, J., Marensi, E., & Wu, X. (2022). Effects of streaky structures on the instability of supersonic boundary layers. In S. Sherwin, P. Schmid, & X. Wu (Eds.), IUTAM Laminar-Turbulent Transition (1st ed., Vol. 38, pp. 587–598). Cham: Springer Nature. https://doi.org/10.1007/978-3-030-67902-6_51","short":"J. Liu, E. Marensi, X. Wu, in:, S. Sherwin, P. Schmid, X. Wu (Eds.), IUTAM Laminar-Turbulent Transition, 1st ed., Springer Nature, Cham, 2022, pp. 587–598.","ieee":"J. Liu, E. Marensi, and X. Wu, “Effects of streaky structures on the instability of supersonic boundary layers,” in IUTAM Laminar-Turbulent Transition, 1st ed., vol. 38, S. Sherwin, P. Schmid, and X. Wu, Eds. Cham: Springer Nature, 2022, pp. 587–598.","mla":"Liu, Jianxin, et al. “Effects of Streaky Structures on the Instability of Supersonic Boundary Layers.” IUTAM Laminar-Turbulent Transition, edited by Spencer Sherwin et al., 1st ed., vol. 38, Springer Nature, 2022, pp. 587–98, doi:10.1007/978-3-030-67902-6_51.","ista":"Liu J, Marensi E, Wu X. 2022.Effects of streaky structures on the instability of supersonic boundary layers. In: IUTAM Laminar-Turbulent Transition. vol. 38, 587–598.","chicago":"Liu, Jianxin, Elena Marensi, and Xuesong Wu. “Effects of Streaky Structures on the Instability of Supersonic Boundary Layers.” In IUTAM Laminar-Turbulent Transition, edited by Spencer Sherwin, Peter Schmid, and Xuesong Wu, 1st ed., 38:587–98. IUTAM Bookseries. Cham: Springer Nature, 2022. https://doi.org/10.1007/978-3-030-67902-6_51."},"intvolume":" 38","place":"Cham","month":"01","scopus_import":"1","oa_version":"None","abstract":[{"lang":"eng","text":"Streaky structures in the boundary layers are often generated by surface roughness elements and/or free-stream turbulence, and are known to have significant effects on boundary-layer instability. In this paper, we investigate the impact of two forms of streaks on the instability of supersonic boundary layers. The first concerns the streaks generated by an array of spanwise periodic and streamwise elongated surface roughness elements, and our interest is how these streaks influence the lower-branch viscous first modes, whose characteristic wavelength and frequency are on the classical triple-deck scales. By adapting the triple-deck theory in the incompressible regime to the supersonic one, we first derived a simplified system which allows for efficient calculation of the streaks. The asymptotic analysis simplifies a bi-global eigenvalue problem to a one-dimensional problem in the spanwise direction, showing that the instability is controlled at leading order solely by the spanwise-dependent wall shear. In the fundamental configuration, the streaks stabilize first modes at low frequencies but destabilize the high-frequency ones. In the subharmonic configuration, the streaks generally destabilize the first mode across the entire frequency band. Importantly, the spanwise even modes are of radiating nature, i.e. they emit acoustic waves spontaneously to the far field. Streaks of the second form are generated by low-frequency vortical disturbances representing free-stream turbulence. They alter the flow in the entire layer and their effects on instability are investigated by solving the inviscid bi-global eigenvalue problem. Different from the incompressible case, a multitude of compressible instability modes exists, of which the dominant mode is an inviscid instability associated with the spanwise shear. In addition, there exists a separate branch of instability modes that have smaller growth rates but are spontaneously radiating."}],"volume":38,"language":[{"iso":"eng"}],"publication_status":"published","publication_identifier":{"eisbn":["9783030679026"],"isbn":["9783030679019"],"eissn":["1875-3493"],"issn":["1875-3507"]},"status":"public","conference":{"name":"IUTAM Symposium","end_date":"2019-09-06","location":"London, United Kingdom","start_date":"2019-09-02"},"type":"book_chapter","series_title":"IUTAM Bookseries","_id":"10820","department":[{"_id":"BjHo"}],"date_updated":"2023-08-03T12:54:59Z"},{"article_type":"original","type":"journal_article","status":"public","keyword":["Mechanical Engineering","Mechanics of Materials","Condensed Matter Physics","Applied Mathematics"],"_id":"12137","department":[{"_id":"BjHo"}],"date_updated":"2023-08-04T08:54:16Z","scopus_import":"1","main_file_link":[{"url":" https://doi.org/10.48550/arXiv.2207.12990","open_access":"1"}],"month":"11","intvolume":" 951","abstract":[{"text":"We investigate the local self-sustained process underlying spiral turbulence in counter-rotating Taylor–Couette flow using a periodic annular domain, shaped as a parallelogram, two of whose sides are aligned with the cylindrical helix described by the spiral pattern. The primary focus of the study is placed on the emergence of drifting–rotating waves (DRW) that capture, in a relatively small domain, the main features of coherent structures typically observed in developed turbulence. The transitional dynamics of the subcritical region, far below the first instability of the laminar circular Couette flow, is determined by the upper and lower branches of DRW solutions originated at saddle-node bifurcations. The mechanism whereby these solutions self-sustain, and the chaotic dynamics they induce, are conspicuously reminiscent of other subcritical shear flows. Remarkably, the flow properties of DRW persist even as the Reynolds number is increased beyond the linear stability threshold of the base flow. Simulations in a narrow parallelogram domain stretched in the azimuthal direction to revolve around the apparatus a full turn confirm that self-sustained vortices eventually concentrate into a localised pattern. The resulting statistical steady state satisfactorily reproduces qualitatively, and to a certain degree also quantitatively, the topology and properties of spiral turbulence as calculated in a large periodic domain of sufficient aspect ratio that is representative of the real system.","lang":"eng"}],"oa_version":"Preprint","volume":951,"publication_identifier":{"eissn":["1469-7645"],"issn":["0022-1120"]},"publication_status":"published","language":[{"iso":"eng"}],"article_number":"A21","author":[{"first_name":"B.","full_name":"Wang, B.","last_name":"Wang"},{"last_name":"Ayats López","orcid":"0000-0001-6572-0621","full_name":"Ayats López, Roger","id":"ab77522d-073b-11ed-8aff-e71b39258362","first_name":"Roger"},{"first_name":"K.","last_name":"Deguchi","full_name":"Deguchi, K."},{"first_name":"F.","full_name":"Mellibovsky, F.","last_name":"Mellibovsky"},{"last_name":"Meseguer","full_name":"Meseguer, A.","first_name":"A."}],"article_processing_charge":"No","external_id":{"arxiv":["2207.12990"],"isi":["000879446900001"]},"title":"Self-sustainment of coherent structures in counter-rotating Taylor–Couette flow","citation":{"apa":"Wang, B., Ayats López, R., Deguchi, K., Mellibovsky, F., & Meseguer, A. (2022). Self-sustainment of coherent structures in counter-rotating Taylor–Couette flow. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2022.828","ama":"Wang B, Ayats López R, Deguchi K, Mellibovsky F, Meseguer A. Self-sustainment of coherent structures in counter-rotating Taylor–Couette flow. Journal of Fluid Mechanics. 2022;951. doi:10.1017/jfm.2022.828","short":"B. Wang, R. Ayats López, K. Deguchi, F. Mellibovsky, A. Meseguer, Journal of Fluid Mechanics 951 (2022).","ieee":"B. Wang, R. Ayats López, K. Deguchi, F. Mellibovsky, and A. Meseguer, “Self-sustainment of coherent structures in counter-rotating Taylor–Couette flow,” Journal of Fluid Mechanics, vol. 951. Cambridge University Press, 2022.","mla":"Wang, B., et al. “Self-Sustainment of Coherent Structures in Counter-Rotating Taylor–Couette Flow.” Journal of Fluid Mechanics, vol. 951, A21, Cambridge University Press, 2022, doi:10.1017/jfm.2022.828.","ista":"Wang B, Ayats López R, Deguchi K, Mellibovsky F, Meseguer A. 2022. Self-sustainment of coherent structures in counter-rotating Taylor–Couette flow. Journal of Fluid Mechanics. 951, A21.","chicago":"Wang, B., Roger Ayats López, K. Deguchi, F. Mellibovsky, and A. Meseguer. “Self-Sustainment of Coherent Structures in Counter-Rotating Taylor–Couette Flow.” Journal of Fluid Mechanics. Cambridge University Press, 2022. https://doi.org/10.1017/jfm.2022.828."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","publisher":"Cambridge University Press","quality_controlled":"1","oa":1,"acknowledgement":"K.D.’s research was supported by an Australian Research Council Discovery Early Career\r\nResearcher Award (DE170100171). B.W., R.A., F.M. and A.M. research was supported by the Spanish Ministerio de Economía y Competitivdad (grant numbers FIS2016-77849-R and FIS2017-85794-P) and Ministerio de Ciencia e Innovación (grant number PID2020-114043GB-I00) and the Generalitat de Catalunya (grant 2017-SGR-785). B.W.’s research was also supported by the Chinese Scholarship Council (grant CSC no. 201806440152).","date_published":"2022-11-07T00:00:00Z","doi":"10.1017/jfm.2022.828","date_created":"2023-01-12T12:04:17Z","isi":1,"year":"2022","day":"07","publication":"Journal of Fluid Mechanics"},{"date_updated":"2023-08-04T09:51:17Z","ddc":["530"],"file_date_updated":"2023-01-30T09:41:12Z","department":[{"_id":"MaSe"},{"_id":"BjHo"},{"_id":"NanoFab"}],"_id":"12259","type":"journal_article","article_type":"original","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"status":"public","keyword":["Applied Mathematics","General Physics and Astronomy","Mathematical Physics","Statistical and Nonlinear Physics"],"publication_identifier":{"issn":["1054-1500"],"eissn":["1089-7682"]},"publication_status":"published","file":[{"access_level":"open_access","relation":"main_file","content_type":"application/pdf","checksum":"17881eff8b21969359a2dd64620120ba","file_id":"12445","success":1,"creator":"dernst","date_updated":"2023-01-30T09:41:12Z","file_size":3209644,"date_created":"2023-01-30T09:41:12Z","file_name":"2022_Chaos_Choueiri.pdf"}],"language":[{"iso":"eng"}],"issue":"9","volume":32,"abstract":[{"lang":"eng","text":"Theoretical foundations of chaos have been predominantly laid out for finite-dimensional dynamical systems, such as the three-body problem in classical mechanics and the Lorenz model in dissipative systems. In contrast, many real-world chaotic phenomena, e.g., weather, arise in systems with many (formally infinite) degrees of freedom, which limits direct quantitative analysis of such systems using chaos theory. In the present work, we demonstrate that the hydrodynamic pilot-wave systems offer a bridge between low- and high-dimensional chaotic phenomena by allowing for a systematic study of how the former connects to the latter. Specifically, we present experimental results, which show the formation of low-dimensional chaotic attractors upon destabilization of regular dynamics and a final transition to high-dimensional chaos via the merging of distinct chaotic regions through a crisis bifurcation. Moreover, we show that the post-crisis dynamics of the system can be rationalized as consecutive scatterings from the nonattracting chaotic sets with lifetimes following exponential distributions. "}],"oa_version":"Published Version","scopus_import":"1","month":"09","intvolume":" 32","citation":{"short":"G.H. Choueiri, B. Suri, J. Merrin, M. Serbyn, B. Hof, N.B. Budanur, Chaos: An Interdisciplinary Journal of Nonlinear Science 32 (2022).","ieee":"G. H. Choueiri, B. Suri, J. Merrin, M. Serbyn, B. Hof, and N. B. Budanur, “Crises and chaotic scattering in hydrodynamic pilot-wave experiments,” Chaos: An Interdisciplinary Journal of Nonlinear Science, vol. 32, no. 9. AIP Publishing, 2022.","ama":"Choueiri GH, Suri B, Merrin J, Serbyn M, Hof B, Budanur NB. Crises and chaotic scattering in hydrodynamic pilot-wave experiments. Chaos: An Interdisciplinary Journal of Nonlinear Science. 2022;32(9). doi:10.1063/5.0102904","apa":"Choueiri, G. H., Suri, B., Merrin, J., Serbyn, M., Hof, B., & Budanur, N. B. (2022). Crises and chaotic scattering in hydrodynamic pilot-wave experiments. Chaos: An Interdisciplinary Journal of Nonlinear Science. AIP Publishing. https://doi.org/10.1063/5.0102904","mla":"Choueiri, George H., et al. “Crises and Chaotic Scattering in Hydrodynamic Pilot-Wave Experiments.” Chaos: An Interdisciplinary Journal of Nonlinear Science, vol. 32, no. 9, 093138, AIP Publishing, 2022, doi:10.1063/5.0102904.","ista":"Choueiri GH, Suri B, Merrin J, Serbyn M, Hof B, Budanur NB. 2022. Crises and chaotic scattering in hydrodynamic pilot-wave experiments. Chaos: An Interdisciplinary Journal of Nonlinear Science. 32(9), 093138.","chicago":"Choueiri, George H, Balachandra Suri, Jack Merrin, Maksym Serbyn, Björn Hof, and Nazmi B Budanur. “Crises and Chaotic Scattering in Hydrodynamic Pilot-Wave Experiments.” Chaos: An Interdisciplinary Journal of Nonlinear Science. AIP Publishing, 2022. https://doi.org/10.1063/5.0102904."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","author":[{"first_name":"George H","id":"448BD5BC-F248-11E8-B48F-1D18A9856A87","last_name":"Choueiri","full_name":"Choueiri, George H"},{"first_name":"Balachandra","id":"47A5E706-F248-11E8-B48F-1D18A9856A87","last_name":"Suri","full_name":"Suri, Balachandra"},{"last_name":"Merrin","orcid":"0000-0001-5145-4609","full_name":"Merrin, Jack","first_name":"Jack","id":"4515C308-F248-11E8-B48F-1D18A9856A87"},{"orcid":"0000-0002-2399-5827","full_name":"Serbyn, Maksym","last_name":"Serbyn","first_name":"Maksym","id":"47809E7E-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof"},{"first_name":"Nazmi B","id":"3EA1010E-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0003-0423-5010","full_name":"Budanur, Nazmi B","last_name":"Budanur"}],"article_processing_charge":"No","external_id":{"arxiv":["2206.01531"],"isi":["000861009600005"]},"title":"Crises and chaotic scattering in hydrodynamic pilot-wave experiments","article_number":"093138","isi":1,"has_accepted_license":"1","year":"2022","day":"26","publication":"Chaos: An Interdisciplinary Journal of Nonlinear Science","doi":"10.1063/5.0102904","date_published":"2022-09-26T00:00:00Z","date_created":"2023-01-16T09:58:16Z","acknowledgement":"This work was partially funded by the Institute of Science and Technology Austria Interdisciplinary Project Committee Grant “Pilot-Wave Hydrodynamics: Chaos and Quantum Analogies.”","quality_controlled":"1","publisher":"AIP Publishing","oa":1},{"issue":"8","volume":7,"publication_status":"published","publication_identifier":{"issn":["2469-990X"]},"language":[{"iso":"eng"}],"main_file_link":[{"url":" https://doi.org/10.48550/arXiv.2205.12871","open_access":"1"}],"scopus_import":"1","intvolume":" 7","month":"08","abstract":[{"text":"We report frictional drag reduction and a complete flow relaminarization of elastic turbulence (ET) at vanishing inertia in a viscoelastic channel flow past an obstacle. We show that the intensity of the observed elastic waves and wall-normal vorticity correlate well with the measured drag above the onset of ET. Moreover, we find that the elastic wave frequency grows with the Weissenberg number, and at sufficiently high frequency it causes a decay of the elastic waves, resulting in ET attenuation and drag reduction. Thus, this allows us to substantiate a physical mechanism, involving the interaction of elastic waves with wall-normal vorticity fluctuations, leading to the drag reduction and relaminarization phenomena at low Reynolds number.","lang":"eng"}],"oa_version":"Preprint","department":[{"_id":"BjHo"}],"date_updated":"2023-08-04T10:26:40Z","type":"journal_article","article_type":"original","keyword":["Fluid Flow and Transfer Processes","Modeling and Simulation","Computational Mechanics"],"status":"public","_id":"12279","date_created":"2023-01-16T10:02:40Z","date_published":"2022-08-03T00:00:00Z","doi":"10.1103/physrevfluids.7.l081301","year":"2022","isi":1,"publication":"Physical Review Fluids","day":"03","oa":1,"quality_controlled":"1","publisher":"American Physical Society","acknowledgement":"We thank G. Falkovich for discussion and Guy Han for technical support. We are grateful to N. Jha for his help in µPIV measurements. This work is partially supported by the grants from\r\nIsrael Science Foundation (ISF; grant #882/15 and grant #784/19) and Binational USA-Israel Foundation (BSF;grant #2016145). ","external_id":{"arxiv":["2205.12871"],"isi":["000836397000001"]},"article_processing_charge":"No","author":[{"first_name":"M. Vijay","last_name":"Kumar","full_name":"Kumar, M. Vijay"},{"full_name":"Varshney, Atul","orcid":"0000-0002-3072-5999","last_name":"Varshney","first_name":"Atul","id":"2A2006B2-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Dongyang","full_name":"Li, Dongyang","last_name":"Li"},{"first_name":"Victor","last_name":"Steinberg","full_name":"Steinberg, Victor"}],"title":"Relaminarization of elastic turbulence","citation":{"chicago":"Kumar, M. Vijay, Atul Varshney, Dongyang Li, and Victor Steinberg. “Relaminarization of Elastic Turbulence.” Physical Review Fluids. American Physical Society, 2022. https://doi.org/10.1103/physrevfluids.7.l081301.","ista":"Kumar MV, Varshney A, Li D, Steinberg V. 2022. Relaminarization of elastic turbulence. Physical Review Fluids. 7(8), L081301.","mla":"Kumar, M. Vijay, et al. “Relaminarization of Elastic Turbulence.” Physical Review Fluids, vol. 7, no. 8, L081301, American Physical Society, 2022, doi:10.1103/physrevfluids.7.l081301.","apa":"Kumar, M. V., Varshney, A., Li, D., & Steinberg, V. (2022). Relaminarization of elastic turbulence. Physical Review Fluids. American Physical Society. https://doi.org/10.1103/physrevfluids.7.l081301","ama":"Kumar MV, Varshney A, Li D, Steinberg V. Relaminarization of elastic turbulence. Physical Review Fluids. 2022;7(8). doi:10.1103/physrevfluids.7.l081301","ieee":"M. V. Kumar, A. Varshney, D. Li, and V. Steinberg, “Relaminarization of elastic turbulence,” Physical Review Fluids, vol. 7, no. 8. American Physical Society, 2022.","short":"M.V. Kumar, A. Varshney, D. Li, V. Steinberg, Physical Review Fluids 7 (2022)."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","article_number":"L081301"},{"article_type":"original","type":"journal_article","status":"public","keyword":["Condensed Matter Physics","Fluid Flow and Transfer Processes","Mechanics of Materials","Computational Mechanics","Mechanical Engineering"],"_id":"12146","department":[{"_id":"BjHo"}],"date_updated":"2023-10-03T11:07:58Z","scopus_import":"1","main_file_link":[{"open_access":"1","url":"https://upcommons.upc.edu/handle/2117/385635"}],"month":"11","intvolume":" 34","abstract":[{"lang":"eng","text":"In this paper, we explore the stability and dynamical relevance of a wide variety of steady, time-periodic, quasiperiodic, and chaotic flows arising between orthogonally stretching parallel plates. We first explore the stability of all the steady flow solution families formerly identified by Ayats et al. [“Flows between orthogonally stretching parallel plates,” Phys. Fluids 33, 024103 (2021)], concluding that only the one that originates from the Stokesian approximation is actually stable. When both plates are shrinking at identical or nearly the same deceleration rates, this Stokesian flow exhibits a Hopf bifurcation that leads to stable time-periodic regimes. The resulting time-periodic orbits or flows are tracked for different Reynolds numbers and stretching rates while monitoring their Floquet exponents to identify secondary instabilities. It is found that these time-periodic flows also exhibit Neimark–Sacker bifurcations, generating stable quasiperiodic flows (tori) that may sometimes give rise to chaotic dynamics through a Ruelle–Takens–Newhouse scenario. However, chaotic dynamics is unusually observed, as the quasiperiodic flows generally become phase-locked through a resonance mechanism before a strange attractor may arise, thus restoring the time-periodicity of the flow. In this work, we have identified and tracked four different resonance regions, also known as Arnold tongues or horns. In particular, the 1 : 4 strong resonance region is explored in great detail, where the identified scenarios are in very good agreement with normal form theory. "}],"oa_version":"Submitted Version","issue":"11","volume":34,"publication_identifier":{"issn":["1070-6631"],"eissn":["1089-7666"]},"publication_status":"published","language":[{"iso":"eng"}],"article_number":"114111","author":[{"full_name":"Wang, B.","last_name":"Wang","first_name":"B."},{"id":"ab77522d-073b-11ed-8aff-e71b39258362","first_name":"Roger","orcid":"0000-0001-6572-0621","full_name":"Ayats López, Roger","last_name":"Ayats López"},{"last_name":"Meseguer","full_name":"Meseguer, A.","first_name":"A."},{"first_name":"F.","last_name":"Marques","full_name":"Marques, F."}],"external_id":{"isi":["000880665300024"]},"article_processing_charge":"No","title":"Phase-locking flows between orthogonally stretching parallel plates","citation":{"mla":"Wang, B., et al. “Phase-Locking Flows between Orthogonally Stretching Parallel Plates.” Physics of Fluids, vol. 34, no. 11, 114111, AIP Publishing, 2022, doi:10.1063/5.0124152.","ama":"Wang B, Ayats López R, Meseguer A, Marques F. Phase-locking flows between orthogonally stretching parallel plates. Physics of Fluids. 2022;34(11). doi:10.1063/5.0124152","apa":"Wang, B., Ayats López, R., Meseguer, A., & Marques, F. (2022). Phase-locking flows between orthogonally stretching parallel plates. Physics of Fluids. AIP Publishing. https://doi.org/10.1063/5.0124152","short":"B. Wang, R. Ayats López, A. Meseguer, F. Marques, Physics of Fluids 34 (2022).","ieee":"B. Wang, R. Ayats López, A. Meseguer, and F. Marques, “Phase-locking flows between orthogonally stretching parallel plates,” Physics of Fluids, vol. 34, no. 11. AIP Publishing, 2022.","chicago":"Wang, B., Roger Ayats López, A. Meseguer, and F. Marques. “Phase-Locking Flows between Orthogonally Stretching Parallel Plates.” Physics of Fluids. AIP Publishing, 2022. https://doi.org/10.1063/5.0124152.","ista":"Wang B, Ayats López R, Meseguer A, Marques F. 2022. Phase-locking flows between orthogonally stretching parallel plates. Physics of Fluids. 34(11), 114111."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","publisher":"AIP Publishing","quality_controlled":"1","oa":1,"acknowledgement":"This work was supported by the Spanish MINECO under Grant Nos. FIS2017-85794-P and PRX18/00179, the Spanish MICINN through Grant No. PID2020-114043GB-I00, and the\r\nGeneralitat de Catalunya under Grant No. 2017-SGR-785. B.W.’s research was also supported by the Chinese Scholarship Council through Grant CSC No. 201806440152.","doi":"10.1063/5.0124152","date_published":"2022-11-04T00:00:00Z","date_created":"2023-01-12T12:06:58Z","isi":1,"year":"2022","day":"04","publication":"Physics of Fluids"},{"status":"public","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"article_type":"original","type":"journal_article","_id":"10791","file_date_updated":"2023-08-16T08:00:30Z","department":[{"_id":"SiHi"},{"_id":"BjHo"},{"_id":"LifeSc"},{"_id":"EM-Fac"}],"ddc":["570"],"date_updated":"2023-11-30T10:55:12Z","intvolume":" 1","month":"07","oa_version":"Published Version","abstract":[{"lang":"eng","text":"The mammalian neocortex is composed of diverse neuronal and glial cell classes that broadly arrange in six distinct laminae. Cortical layers emerge during development and defects in the developmental programs that orchestrate cortical lamination are associated with neurodevelopmental diseases. The developmental principle of cortical layer formation depends on concerted radial projection neuron migration, from their birthplace to their final target position. Radial migration occurs in defined sequential steps, regulated by a large array of signaling pathways. However, based on genetic loss-of-function experiments, most studies have thus far focused on the role of cell-autonomous gene function. Yet, cortical neuron migration in situ is a complex process and migrating neurons traverse along diverse cellular compartments and environments. The role of tissue-wide properties and genetic state in radial neuron migration is however not clear. Here we utilized mosaic analysis with double markers (MADM) technology to either sparsely or globally delete gene function, followed by quantitative single-cell phenotyping. The MADM-based gene ablation paradigms in combination with computational modeling demonstrated that global tissue-wide effects predominate cell-autonomous gene function albeit in a gene-specific manner. Our results thus suggest that the genetic landscape in a tissue critically affects the overall migration phenotype of individual cortical projection neurons. In a broader context, our findings imply that global tissue-wide effects represent an essential component of the underlying etiology associated with focal malformations of cortical development in particular, and neurological diseases in general."}],"acknowledged_ssus":[{"_id":"LifeSc"},{"_id":"PreCl"},{"_id":"Bio"}],"ec_funded":1,"related_material":{"record":[{"status":"public","id":"12726","relation":"dissertation_contains"},{"status":"public","id":"14530","relation":"dissertation_contains"}]},"issue":"1","volume":1,"language":[{"iso":"eng"}],"file":[{"success":1,"file_id":"14061","checksum":"822e76e056c07099d1fb27d1ece5941b","content_type":"application/pdf","relation":"main_file","access_level":"open_access","file_name":"2023_OxfordOpenNeuroscience_Hansen.pdf","date_created":"2023-08-16T08:00:30Z","file_size":4846551,"date_updated":"2023-08-16T08:00:30Z","creator":"dernst"}],"publication_status":"published","publication_identifier":{"eissn":["2753-149X"]},"project":[{"_id":"25D61E48-B435-11E9-9278-68D0E5697425","call_identifier":"FP7","name":"Molecular Mechanisms of Cerebral Cortex Development","grant_number":"618444"},{"name":"Molecular Mechanisms of Radial Neuronal Migration","grant_number":"24812","_id":"2625A13E-B435-11E9-9278-68D0E5697425"}],"article_number":"kvac009","title":"Tissue-wide effects override cell-intrinsic gene function in radial neuron migration","article_processing_charge":"No","author":[{"id":"38853E16-F248-11E8-B48F-1D18A9856A87","first_name":"Andi H","full_name":"Hansen, Andi H","last_name":"Hansen"},{"first_name":"Florian","id":"48EA0138-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0002-7462-0048","full_name":"Pauler, Florian","last_name":"Pauler"},{"orcid":"0000-0003-4844-6311","full_name":"Riedl, Michael","last_name":"Riedl","first_name":"Michael","id":"3BE60946-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Streicher","full_name":"Streicher, Carmen","id":"36BCB99C-F248-11E8-B48F-1D18A9856A87","first_name":"Carmen"},{"last_name":"Heger","full_name":"Heger, Anna-Magdalena","first_name":"Anna-Magdalena","id":"4B76FFD2-F248-11E8-B48F-1D18A9856A87"},{"id":"2D6B7A9A-F248-11E8-B48F-1D18A9856A87","first_name":"Susanne","last_name":"Laukoter","orcid":"0000-0002-7903-3010","full_name":"Laukoter, Susanne"},{"id":"4DF26D8C-F248-11E8-B48F-1D18A9856A87","first_name":"Christoph M","last_name":"Sommer","full_name":"Sommer, Christoph M","orcid":"0000-0003-1216-9105"},{"full_name":"Nicolas, Armel","last_name":"Nicolas","first_name":"Armel","id":"2A103192-F248-11E8-B48F-1D18A9856A87"},{"full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof","first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Li Huei","full_name":"Tsai, Li Huei","last_name":"Tsai"},{"first_name":"Thomas","full_name":"Rülicke, Thomas","last_name":"Rülicke"},{"id":"37B36620-F248-11E8-B48F-1D18A9856A87","first_name":"Simon","last_name":"Hippenmeyer","orcid":"0000-0003-2279-1061","full_name":"Hippenmeyer, Simon"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"mla":"Hansen, Andi H., et al. “Tissue-Wide Effects Override Cell-Intrinsic Gene Function in Radial Neuron Migration.” Oxford Open Neuroscience, vol. 1, no. 1, kvac009, Oxford Academic, 2022, doi:10.1093/oons/kvac009.","short":"A.H. Hansen, F. Pauler, M. Riedl, C. Streicher, A.-M. Heger, S. Laukoter, C.M. Sommer, A. Nicolas, B. Hof, L.H. Tsai, T. Rülicke, S. Hippenmeyer, Oxford Open Neuroscience 1 (2022).","ieee":"A. H. Hansen et al., “Tissue-wide effects override cell-intrinsic gene function in radial neuron migration,” Oxford Open Neuroscience, vol. 1, no. 1. Oxford Academic, 2022.","apa":"Hansen, A. H., Pauler, F., Riedl, M., Streicher, C., Heger, A.-M., Laukoter, S., … Hippenmeyer, S. (2022). Tissue-wide effects override cell-intrinsic gene function in radial neuron migration. Oxford Open Neuroscience. Oxford Academic. https://doi.org/10.1093/oons/kvac009","ama":"Hansen AH, Pauler F, Riedl M, et al. Tissue-wide effects override cell-intrinsic gene function in radial neuron migration. Oxford Open Neuroscience. 2022;1(1). doi:10.1093/oons/kvac009","chicago":"Hansen, Andi H, Florian Pauler, Michael Riedl, Carmen Streicher, Anna-Magdalena Heger, Susanne Laukoter, Christoph M Sommer, et al. “Tissue-Wide Effects Override Cell-Intrinsic Gene Function in Radial Neuron Migration.” Oxford Open Neuroscience. Oxford Academic, 2022. https://doi.org/10.1093/oons/kvac009.","ista":"Hansen AH, Pauler F, Riedl M, Streicher C, Heger A-M, Laukoter S, Sommer CM, Nicolas A, Hof B, Tsai LH, Rülicke T, Hippenmeyer S. 2022. Tissue-wide effects override cell-intrinsic gene function in radial neuron migration. Oxford Open Neuroscience. 1(1), kvac009."},"oa":1,"quality_controlled":"1","publisher":"Oxford Academic","acknowledgement":"A.H.H. was a recipient of a DOC Fellowship (24812) of the Austrian Academy of Sciences. This work also received support from IST Austria institutional funds; the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme (FP7/2007–2013) under REA grant agreement No 618444 to S.H.\r\nAPC funding was obtained by IST Austria institutional funds.\r\nWe thank A. Sommer and C. Czepe (VBCF GmbH, NGS Unit), L. Andersen, J. Sonntag and J. Renno for technical support and/or initial experiments; M. Sixt, J. Nimpf and all members of the Hippenmeyer lab for discussion. This research was supported by the Scientific Service Units of IST Austria through resources provided by the Imaging and Optics Facility, Lab Support Facility and Preclinical Facility.","date_created":"2022-02-25T07:52:11Z","doi":"10.1093/oons/kvac009","date_published":"2022-07-07T00:00:00Z","publication":"Oxford Open Neuroscience","day":"07","year":"2022","has_accepted_license":"1"},{"_id":"10703","article_type":"original","type":"journal_article","tmp":{"short":"CC BY-NC-ND (4.0)","name":"Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)","legal_code_url":"https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode","image":"/images/cc_by_nc_nd.png"},"status":"public","date_updated":"2024-03-27T23:30:23Z","ddc":["570"],"department":[{"_id":"MiSi"},{"_id":"EM-Fac"},{"_id":"NanoFab"},{"_id":"BjHo"}],"abstract":[{"text":"When crawling through the body, leukocytes often traverse tissues that are densely packed with extracellular matrix and other cells, and this raises the question: How do leukocytes overcome compressive mechanical loads? Here, we show that the actin cortex of leukocytes is mechanoresponsive and that this responsiveness requires neither force sensing via the nucleus nor adhesive interactions with a substrate. Upon global compression of the cell body as well as local indentation of the plasma membrane, Wiskott-Aldrich syndrome protein (WASp) assembles into dot-like structures, providing activation platforms for Arp2/3 nucleated actin patches. These patches locally push against the external load, which can be obstructing collagen fibers or other cells, and thereby create space to facilitate forward locomotion. We show in vitro and in vivo that this WASp function is rate limiting for ameboid leukocyte migration in dense but not in loose environments and is required for trafficking through diverse tissues such as skin and lymph nodes.","lang":"eng"}],"acknowledged_ssus":[{"_id":"LifeSc"},{"_id":"Bio"},{"_id":"EM-Fac"}],"pmid":1,"oa_version":"Published Version","scopus_import":"1","main_file_link":[{"url":"https://www.sciencedirect.com/science/article/pii/S1534580721009497","open_access":"1"}],"month":"01","intvolume":" 57","publication_identifier":{"eissn":["1878-1551"],"issn":["1534-5807"]},"publication_status":"published","language":[{"iso":"eng"}],"issue":"1","related_material":{"record":[{"status":"public","id":"12726","relation":"dissertation_contains"},{"status":"public","id":"14530","relation":"dissertation_contains"},{"relation":"dissertation_contains","id":"12401","status":"public"}]},"volume":57,"ec_funded":1,"license":"https://creativecommons.org/licenses/by-nc-nd/4.0/","project":[{"grant_number":"747687","name":"Mechanical Adaptation of Lamellipodial Actin Networks in Migrating Cells","_id":"260AA4E2-B435-11E9-9278-68D0E5697425","call_identifier":"H2020"},{"grant_number":"724373","name":"Cellular navigation along spatial gradients","_id":"25FE9508-B435-11E9-9278-68D0E5697425","call_identifier":"H2020"}],"citation":{"mla":"Gaertner, Florian, et al. “WASp Triggers Mechanosensitive Actin Patches to Facilitate Immune Cell Migration in Dense Tissues.” Developmental Cell, vol. 57, no. 1, Cell Press ; Elsevier, 2022, p. 47–62.e9, doi:10.1016/j.devcel.2021.11.024.","apa":"Gaertner, F., Reis-Rodrigues, P., de Vries, I., Hons, M., Aguilera, J., Riedl, M., … Sixt, M. K. (2022). WASp triggers mechanosensitive actin patches to facilitate immune cell migration in dense tissues. Developmental Cell. Cell Press ; Elsevier. https://doi.org/10.1016/j.devcel.2021.11.024","ama":"Gaertner F, Reis-Rodrigues P, de Vries I, et al. WASp triggers mechanosensitive actin patches to facilitate immune cell migration in dense tissues. Developmental Cell. 2022;57(1):47-62.e9. doi:10.1016/j.devcel.2021.11.024","ieee":"F. Gaertner et al., “WASp triggers mechanosensitive actin patches to facilitate immune cell migration in dense tissues,” Developmental Cell, vol. 57, no. 1. Cell Press ; Elsevier, p. 47–62.e9, 2022.","short":"F. Gaertner, P. Reis-Rodrigues, I. de Vries, M. Hons, J. Aguilera, M. Riedl, A.F. Leithner, S. Tasciyan, A. Kopf, J. Merrin, V. Zheden, W. Kaufmann, R. Hauschild, M.K. Sixt, Developmental Cell 57 (2022) 47–62.e9.","chicago":"Gaertner, Florian, Patricia Reis-Rodrigues, Ingrid de Vries, Miroslav Hons, Juan Aguilera, Michael Riedl, Alexander F Leithner, et al. “WASp Triggers Mechanosensitive Actin Patches to Facilitate Immune Cell Migration in Dense Tissues.” Developmental Cell. Cell Press ; Elsevier, 2022. https://doi.org/10.1016/j.devcel.2021.11.024.","ista":"Gaertner F, Reis-Rodrigues P, de Vries I, Hons M, Aguilera J, Riedl M, Leithner AF, Tasciyan S, Kopf A, Merrin J, Zheden V, Kaufmann W, Hauschild R, Sixt MK. 2022. WASp triggers mechanosensitive actin patches to facilitate immune cell migration in dense tissues. Developmental Cell. 57(1), 47–62.e9."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","author":[{"last_name":"Gaertner","full_name":"Gaertner, Florian","first_name":"Florian"},{"full_name":"Reis-Rodrigues, Patricia","last_name":"Reis-Rodrigues","first_name":"Patricia"},{"id":"4C7D837E-F248-11E8-B48F-1D18A9856A87","first_name":"Ingrid","last_name":"De Vries","full_name":"De Vries, Ingrid"},{"full_name":"Hons, Miroslav","orcid":"0000-0002-6625-3348","last_name":"Hons","first_name":"Miroslav","id":"4167FE56-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Juan","last_name":"Aguilera","full_name":"Aguilera, Juan"},{"full_name":"Riedl, Michael","orcid":"0000-0003-4844-6311","last_name":"Riedl","first_name":"Michael","id":"3BE60946-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Alexander F","id":"3B1B77E4-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0002-1073-744X","full_name":"Leithner, Alexander F","last_name":"Leithner"},{"first_name":"Saren","id":"4323B49C-F248-11E8-B48F-1D18A9856A87","full_name":"Tasciyan, Saren","orcid":"0000-0003-1671-393X","last_name":"Tasciyan"},{"full_name":"Kopf, Aglaja","orcid":"0000-0002-2187-6656","last_name":"Kopf","first_name":"Aglaja","id":"31DAC7B6-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Merrin","orcid":"0000-0001-5145-4609","full_name":"Merrin, Jack","first_name":"Jack","id":"4515C308-F248-11E8-B48F-1D18A9856A87"},{"id":"39C5A68A-F248-11E8-B48F-1D18A9856A87","first_name":"Vanessa","full_name":"Zheden, Vanessa","orcid":"0000-0002-9438-4783","last_name":"Zheden"},{"first_name":"Walter","id":"3F99E422-F248-11E8-B48F-1D18A9856A87","last_name":"Kaufmann","full_name":"Kaufmann, Walter","orcid":"0000-0001-9735-5315"},{"full_name":"Hauschild, Robert","orcid":"0000-0001-9843-3522","last_name":"Hauschild","id":"4E01D6B4-F248-11E8-B48F-1D18A9856A87","first_name":"Robert"},{"first_name":"Michael K","id":"41E9FBEA-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0002-6620-9179","full_name":"Sixt, Michael K","last_name":"Sixt"}],"article_processing_charge":"No","external_id":{"isi":["000768933800005"],"pmid":["34919802"]},"title":"WASp triggers mechanosensitive actin patches to facilitate immune cell migration in dense tissues","acknowledgement":"We thank N. Darwish-Miranda, F. Leite, F.P. Assen, and A. Eichner for advice and help with experiments. We thank J. Renkawitz, E. Kiermaier, A. Juanes Garcia, and M. Avellaneda for critical reading of the manuscript. We thank M. Driscoll for advice on fluorescent labeling of collagen gels. This research was supported by the Scientific Service Units (SSUs) of IST Austria through resources provided by Molecular Biology Services/Lab Support Facility (LSF)/Bioimaging Facility/Electron Microscopy Facility. This work was funded by grants from the European Research Council ( CoG 724373 ) and the Austrian Science Foundation (FWF) to M.S. F.G. received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no. 747687.","publisher":"Cell Press ; Elsevier","quality_controlled":"1","oa":1,"isi":1,"year":"2022","day":"10","publication":"Developmental Cell","page":"47-62.e9","date_published":"2022-01-10T00:00:00Z","doi":"10.1016/j.devcel.2021.11.024","date_created":"2022-01-30T23:01:33Z"},{"status":"public","article_type":"original","type":"journal_article","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"_id":"8999","file_date_updated":"2021-01-11T07:50:32Z","department":[{"_id":"BjHo"}],"ddc":["530"],"date_updated":"2023-08-07T13:31:07Z","month":"01","intvolume":" 23","scopus_import":"1","oa_version":"Published Version","pmid":1,"abstract":[{"text":"In many basic shear flows, such as pipe, Couette, and channel flow, turbulence does not\r\narise from an instability of the laminar state, and both dynamical states co-exist. With decreasing flow speed (i.e., decreasing Reynolds number) the fraction of fluid in laminar motion increases while turbulence recedes and eventually the entire flow relaminarizes. The first step towards understanding the nature of this transition is to determine if the phase change is of either first or second order. In the former case, the turbulent fraction would drop discontinuously to zero as the Reynolds number decreases while in the latter the process would be continuous. For Couette flow, the flow between two parallel plates, earlier studies suggest a discontinuous scenario. In the present study we realize a Couette flow between two concentric cylinders which allows studies to be carried out in large aspect ratios and for extensive observation times. The presented measurements show that the transition in this circular Couette geometry is continuous suggesting that former studies were limited by finite size effects. A further characterization of this transition, in particular its relation to the directed percolation universality class, requires even larger system sizes than presently available. ","lang":"eng"}],"volume":23,"issue":"1","file":[{"content_type":"application/pdf","relation":"main_file","access_level":"open_access","success":1,"file_id":"9003","checksum":"3ba3dd8b7eecff713b72c5e9ba30d626","file_size":9456389,"date_updated":"2021-01-11T07:50:32Z","creator":"dernst","file_name":"2021_Entropy_Avila.pdf","date_created":"2021-01-11T07:50:32Z"}],"language":[{"iso":"eng"}],"publication_identifier":{"eissn":["1099-4300"]},"publication_status":"published","article_number":"58","title":"Second-order phase transition in counter-rotating taylor-couette flow experiment","author":[{"first_name":"Kerstin","id":"fcf74381-53e1-11eb-a6dc-b0e2acf78757","full_name":"Avila, Kerstin","last_name":"Avila"},{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","last_name":"Hof","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn"}],"external_id":{"pmid":["33396499"],"isi":["000610135400001"]},"article_processing_charge":"No","user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"chicago":"Avila, Kerstin, and Björn Hof. “Second-Order Phase Transition in Counter-Rotating Taylor-Couette Flow Experiment.” Entropy. MDPI, 2021. https://doi.org/10.3390/e23010058.","ista":"Avila K, Hof B. 2021. Second-order phase transition in counter-rotating taylor-couette flow experiment. Entropy. 23(1), 58.","mla":"Avila, Kerstin, and Björn Hof. “Second-Order Phase Transition in Counter-Rotating Taylor-Couette Flow Experiment.” Entropy, vol. 23, no. 1, 58, MDPI, 2021, doi:10.3390/e23010058.","apa":"Avila, K., & Hof, B. (2021). Second-order phase transition in counter-rotating taylor-couette flow experiment. Entropy. MDPI. https://doi.org/10.3390/e23010058","ama":"Avila K, Hof B. Second-order phase transition in counter-rotating taylor-couette flow experiment. Entropy. 2021;23(1). doi:10.3390/e23010058","ieee":"K. Avila and B. Hof, “Second-order phase transition in counter-rotating taylor-couette flow experiment,” Entropy, vol. 23, no. 1. MDPI, 2021.","short":"K. Avila, B. Hof, Entropy 23 (2021)."},"quality_controlled":"1","publisher":"MDPI","oa":1,"acknowledgement":"This research was funded by the Central Research Development Fund of the University of\r\nBremen grant number ZF04B /2019/FB04 Avila_Kerstin (“Independent Project for Postdocs”). Shreyas Jalikop is acknowledged for recording some of the lifetime measurements\r\n","doi":"10.3390/e23010058","date_published":"2021-01-01T00:00:00Z","date_created":"2021-01-10T23:01:17Z","day":"01","publication":"Entropy","has_accepted_license":"1","isi":1,"year":"2021"},{"acknowledgement":"We thank Y. Duguet, S. Gomé, G. Lemoult, T. Liu, B. Semin and L.S. Tuckerman for\r\nfruitful discussions. \r\nThis work was supported by a grant, TRANSFLOW, provided by the Agence Nationale de\r\nla Recherche (ANR). A.M.P. was partially supported by the French Embassy in Russia (I.I. Mechnikov scholarship) and by the Russian Science Foundation (project no. 18-79-00189). L.K. was partially supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 754411.","oa":1,"quality_controlled":"1","publisher":"Cambridge University Press","year":"2021","isi":1,"has_accepted_license":"1","publication":"Journal of Fluid Mechanics","day":"15","date_created":"2021-02-28T23:01:25Z","doi":"10.1017/jfm.2020.1089","date_published":"2021-02-15T00:00:00Z","article_number":"A24","project":[{"_id":"260C2330-B435-11E9-9278-68D0E5697425","call_identifier":"H2020","name":"ISTplus - Postdoctoral Fellowships","grant_number":"754411"}],"citation":{"ieee":"L. Klotz, A. M. Pavlenko, and J. E. Wesfreid, “Experimental measurements in plane Couette-Poiseuille flow: Dynamics of the large- and small-scale flow,” Journal of Fluid Mechanics, vol. 912. Cambridge University Press, 2021.","short":"L. Klotz, A.M. Pavlenko, J.E. Wesfreid, Journal of Fluid Mechanics 912 (2021).","ama":"Klotz L, Pavlenko AM, Wesfreid JE. Experimental measurements in plane Couette-Poiseuille flow: Dynamics of the large- and small-scale flow. Journal of Fluid Mechanics. 2021;912. doi:10.1017/jfm.2020.1089","apa":"Klotz, L., Pavlenko, A. M., & Wesfreid, J. E. (2021). Experimental measurements in plane Couette-Poiseuille flow: Dynamics of the large- and small-scale flow. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2020.1089","mla":"Klotz, Lukasz, et al. “Experimental Measurements in Plane Couette-Poiseuille Flow: Dynamics of the Large- and Small-Scale Flow.” Journal of Fluid Mechanics, vol. 912, A24, Cambridge University Press, 2021, doi:10.1017/jfm.2020.1089.","ista":"Klotz L, Pavlenko AM, Wesfreid JE. 2021. Experimental measurements in plane Couette-Poiseuille flow: Dynamics of the large- and small-scale flow. Journal of Fluid Mechanics. 912, A24.","chicago":"Klotz, Lukasz, A. M. Pavlenko, and J. E. Wesfreid. “Experimental Measurements in Plane Couette-Poiseuille Flow: Dynamics of the Large- and Small-Scale Flow.” Journal of Fluid Mechanics. Cambridge University Press, 2021. https://doi.org/10.1017/jfm.2020.1089."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","article_processing_charge":"Yes (via OA deal)","external_id":{"isi":["000618034400001"]},"author":[{"first_name":"Lukasz","id":"2C9AF1C2-F248-11E8-B48F-1D18A9856A87","last_name":"Klotz","orcid":"0000-0003-1740-7635","full_name":"Klotz, Lukasz"},{"first_name":"A. M.","full_name":"Pavlenko, A. M.","last_name":"Pavlenko"},{"last_name":"Wesfreid","full_name":"Wesfreid, J. E.","first_name":"J. E."}],"title":"Experimental measurements in plane Couette-Poiseuille flow: Dynamics of the large- and small-scale flow","abstract":[{"text":"In this paper we experimentally study the transitional range of Reynolds numbers in\r\nplane Couette–Poiseuille flow, focusing our attention on the localized turbulent structures\r\ntriggered by a strong impulsive jet and the large-scale flow generated around these\r\nstructures. We present a detailed investigation of the large-scale flow and show how\r\nits amplitude depends on Reynolds number and amplitude perturbation. In addition,\r\nwe characterize the initial dynamics of the localized turbulent spot, which includes the\r\ncoupling between the small and large scales, as well as the dependence of the advection\r\nspeed on the large-scale flow generated around the spot. Finally, we provide the first\r\nexperimental measurements of the large-scale flow around an oblique turbulent band.","lang":"eng"}],"oa_version":"Published Version","scopus_import":"1","intvolume":" 912","month":"02","publication_status":"published","publication_identifier":{"issn":["0022-1120"],"eissn":["1469-7645"]},"language":[{"iso":"eng"}],"file":[{"access_level":"open_access","relation":"main_file","content_type":"application/pdf","checksum":"b8020d6338667673e34fde0608913dd2","file_id":"9220","success":1,"creator":"dernst","date_updated":"2021-03-03T09:49:34Z","file_size":4124471,"date_created":"2021-03-03T09:49:34Z","file_name":"2021_JourFluidMechanics_Klotz.pdf"}],"ec_funded":1,"volume":912,"_id":"9207","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"type":"journal_article","article_type":"original","status":"public","date_updated":"2023-08-07T13:55:40Z","ddc":["530"],"department":[{"_id":"BjHo"}],"file_date_updated":"2021-03-03T09:49:34Z"},{"article_number":"A65","user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"chicago":"Liu, T., B. Semin, Lukasz Klotz, R. Godoy-Diana, J. E. Wesfreid, and T. Mullin. “Decay of Streaks and Rolls in Plane Couette-Poiseuille Flow.” Journal of Fluid Mechanics. Cambridge University Press, 2021. https://doi.org/10.1017/jfm.2021.89.","ista":"Liu T, Semin B, Klotz L, Godoy-Diana R, Wesfreid JE, Mullin T. 2021. Decay of streaks and rolls in plane Couette-Poiseuille flow. Journal of Fluid Mechanics. 915, A65.","mla":"Liu, T., et al. “Decay of Streaks and Rolls in Plane Couette-Poiseuille Flow.” Journal of Fluid Mechanics, vol. 915, A65, Cambridge University Press, 2021, doi:10.1017/jfm.2021.89.","ama":"Liu T, Semin B, Klotz L, Godoy-Diana R, Wesfreid JE, Mullin T. Decay of streaks and rolls in plane Couette-Poiseuille flow. Journal of Fluid Mechanics. 2021;915. doi:10.1017/jfm.2021.89","apa":"Liu, T., Semin, B., Klotz, L., Godoy-Diana, R., Wesfreid, J. E., & Mullin, T. (2021). Decay of streaks and rolls in plane Couette-Poiseuille flow. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2021.89","short":"T. Liu, B. Semin, L. Klotz, R. Godoy-Diana, J.E. Wesfreid, T. Mullin, Journal of Fluid Mechanics 915 (2021).","ieee":"T. Liu, B. Semin, L. Klotz, R. Godoy-Diana, J. E. Wesfreid, and T. Mullin, “Decay of streaks and rolls in plane Couette-Poiseuille flow,” Journal of Fluid Mechanics, vol. 915. Cambridge University Press, 2021."},"title":"Decay of streaks and rolls in plane Couette-Poiseuille flow","article_processing_charge":"No","external_id":{"isi":["000629677500001"],"arxiv":["2008.08851"]},"author":[{"first_name":"T.","full_name":"Liu, T.","last_name":"Liu"},{"full_name":"Semin, B.","last_name":"Semin","first_name":"B."},{"last_name":"Klotz","full_name":"Klotz, Lukasz","orcid":"0000-0003-1740-7635","id":"2C9AF1C2-F248-11E8-B48F-1D18A9856A87","first_name":"Lukasz"},{"first_name":"R.","full_name":"Godoy-Diana, R.","last_name":"Godoy-Diana"},{"first_name":"J. E.","last_name":"Wesfreid","full_name":"Wesfreid, J. E."},{"last_name":"Mullin","full_name":"Mullin, T.","first_name":"T."}],"acknowledgement":"We gratefully acknowledge Joran Rolland, Yohann Duguet, Romain Monchaux, S´ebastien Gom´e, Laurette Tuckerman, Dwight Barkley, Olivier Dauchot and Sabine Bottin for fruitful discussions. We thank Xavier Benoit-Gonin, Amaury Fourgeaud, Thierry Darnige, Olivier Brouard and Justine Laurent for technical help. This work has benefited from the ANR TransFlow, and by starting grants obtained by B.S. from CNRS (INSIS) and ESPCI. T.M. was\r\nsupported by a Joliot visiting professorship grant from ESPCI.","oa":1,"publisher":"Cambridge University Press","quality_controlled":"1","publication":"Journal of Fluid Mechanics","day":"17","year":"2021","isi":1,"date_created":"2021-03-28T22:01:42Z","doi":"10.1017/jfm.2021.89","date_published":"2021-03-17T00:00:00Z","_id":"9297","status":"public","type":"journal_article","article_type":"original","date_updated":"2023-08-07T14:30:11Z","department":[{"_id":"BjHo"}],"oa_version":"Preprint","abstract":[{"lang":"eng","text":"We report the results of an experimental investigation into the decay of turbulence in plane Couette–Poiseuille flow using ‘quench’ experiments where the flow laminarises after a sudden reduction in Reynolds number Re. Specifically, we study the velocity field in the streamwise–spanwise plane. We show that the spanwise velocity containing rolls decays faster than the streamwise velocity, which displays elongated regions of higher or lower velocity called streaks. At final Reynolds numbers above 425, the decay of streaks displays two stages: first a slow decay when rolls are present and secondly a more rapid decay of streaks alone. The difference in behaviour results from the regeneration of streaks by rolls, called the lift-up effect. We define the turbulent fraction as the portion of the flow containing turbulence and this is estimated by thresholding the spanwise velocity component. It decreases linearly with time in the whole range of final Re. The corresponding decay slope increases linearly with final Re. The extrapolated value at which this decay slope vanishes is Reaz≈656±10, close to Reg≈670 at which turbulence is self-sustained. The decay of the energy computed from the spanwise velocity component is found to be exponential. The corresponding decay rate increases linearly with Re, with an extrapolated vanishing value at ReAz≈688±10. This value is also close to the value at which the turbulence is self-sustained, showing that valuable information on the transition can be obtained over a wide range of Re."}],"intvolume":" 915","month":"03","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/2008.08851"}],"scopus_import":"1","language":[{"iso":"eng"}],"publication_status":"published","publication_identifier":{"eissn":["1469-7645"],"issn":["0022-1120"]},"volume":915},{"department":[{"_id":"BjHo"}],"file_date_updated":"2021-05-25T14:18:40Z","date_updated":"2023-08-08T13:45:13Z","ddc":["570"],"article_type":"original","type":"journal_article","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"status":"public","_id":"9407","related_material":{"link":[{"description":"News on IST Homepage","url":"https://ist.ac.at/en/news/smashing-the-covid-curve/","relation":"press_release"}]},"issue":"1","volume":12,"publication_identifier":{"eissn":["20411723"]},"publication_status":"published","file":[{"checksum":"fe26c1b8a7da1ae07a6c03f80ff06ea1","file_id":"9426","success":1,"content_type":"application/pdf","access_level":"open_access","relation":"main_file","date_created":"2021-05-25T14:18:40Z","file_name":"2021_NatureCommunications_Scarselli.pdf","date_updated":"2021-05-25T14:18:40Z","file_size":1176573,"creator":"kschuh"}],"language":[{"iso":"eng"}],"scopus_import":"1","month":"05","intvolume":" 12","abstract":[{"lang":"eng","text":"High impact epidemics constitute one of the largest threats humanity is facing in the 21st century. In the absence of pharmaceutical interventions, physical distancing together with testing, contact tracing and quarantining are crucial in slowing down epidemic dynamics. Yet, here we show that if testing capacities are limited, containment may fail dramatically because such combined countermeasures drastically change the rules of the epidemic transition: Instead of continuous, the response to countermeasures becomes discontinuous. Rather than following the conventional exponential growth, the outbreak that is initially strongly suppressed eventually accelerates and scales faster than exponential during an explosive growth period. As a consequence, containment measures either suffice to stop the outbreak at low total case numbers or fail catastrophically if marginally too weak, thus implying large uncertainties in reliably estimating overall epidemic dynamics, both during initial phases and during second wave scenarios."}],"oa_version":"Published Version","author":[{"id":"40315C30-F248-11E8-B48F-1D18A9856A87","first_name":"Davide","last_name":"Scarselli","orcid":"0000-0001-5227-4271","full_name":"Scarselli, Davide"},{"orcid":"0000-0003-0423-5010","full_name":"Budanur, Nazmi B","last_name":"Budanur","first_name":"Nazmi B","id":"3EA1010E-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Marc","last_name":"Timme","full_name":"Timme, Marc"},{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754"}],"article_processing_charge":"No","external_id":{"isi":["000687305500044"]},"title":"Discontinuous epidemic transition due to limited testing","citation":{"mla":"Scarselli, Davide, et al. “Discontinuous Epidemic Transition Due to Limited Testing.” Nature Communications, vol. 12, no. 1, 2586, Springer Nature, 2021, doi:10.1038/s41467-021-22725-9.","ieee":"D. Scarselli, N. B. Budanur, M. Timme, and B. Hof, “Discontinuous epidemic transition due to limited testing,” Nature Communications, vol. 12, no. 1. Springer Nature, 2021.","short":"D. Scarselli, N.B. Budanur, M. Timme, B. Hof, Nature Communications 12 (2021).","ama":"Scarselli D, Budanur NB, Timme M, Hof B. Discontinuous epidemic transition due to limited testing. Nature Communications. 2021;12(1). doi:10.1038/s41467-021-22725-9","apa":"Scarselli, D., Budanur, N. B., Timme, M., & Hof, B. (2021). Discontinuous epidemic transition due to limited testing. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-021-22725-9","chicago":"Scarselli, Davide, Nazmi B Budanur, Marc Timme, and Björn Hof. “Discontinuous Epidemic Transition Due to Limited Testing.” Nature Communications. Springer Nature, 2021. https://doi.org/10.1038/s41467-021-22725-9.","ista":"Scarselli D, Budanur NB, Timme M, Hof B. 2021. Discontinuous epidemic transition due to limited testing. Nature Communications. 12(1), 2586."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","article_number":"2586","doi":"10.1038/s41467-021-22725-9","date_published":"2021-05-10T00:00:00Z","date_created":"2021-05-23T22:01:42Z","has_accepted_license":"1","isi":1,"year":"2021","day":"10","publication":"Nature Communications","publisher":"Springer Nature","quality_controlled":"1","oa":1,"acknowledgement":"The authors thank Malte Schröder for valuable discussions and creating the scale-free network topologies. B.H. thanks Mukund Vasudevan for helpful discussion. The research by M.T. was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany´s Excellence Strategy–EXC-2068–390729961–Cluster of Excellence Physics of Life of TU Dresden."},{"date_updated":"2023-08-08T13:58:41Z","ddc":["530"],"department":[{"_id":"BjHo"}],"file_date_updated":"2021-08-03T09:53:28Z","_id":"9467","type":"journal_article","article_type":"original","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"status":"public","publication_identifier":{"eissn":["14697645"],"issn":["00221120"]},"publication_status":"published","file":[{"file_name":"2021_JournalFluidMechanics_Marensi.pdf","date_created":"2021-08-03T09:53:28Z","creator":"kschuh","file_size":4087358,"date_updated":"2021-08-03T09:53:28Z","success":1,"file_id":"9766","checksum":"867ad077e45c181c2c5ec1311ba27c41","relation":"main_file","access_level":"open_access","content_type":"application/pdf"}],"language":[{"iso":"eng"}],"volume":919,"abstract":[{"lang":"eng","text":"Turbulence in the flow of fluid through a pipe can be suppressed by buoyancy forces. As the suppression of turbulence leads to severe heat transfer deterioration, this is an important and undesirable phenomenon in both heating and cooling applications. Vertical flow is often considered, as the axial buoyancy force can help drive the flow. With heating measured by the buoyancy parameter 𝐶, our direct numerical simulations show that shear-driven turbulence may either be completely laminarised or it transitions to a relatively quiescent convection-driven state. Buoyancy forces cause a flattening of the base flow profile, which in isothermal pipe flow has recently been linked to complete suppression of turbulence (Kühnen et al., Nat. Phys., vol. 14, 2018, pp. 386–390), and the flattened laminar base profile has enhanced nonlinear stability (Marensi et al., J. Fluid Mech., vol. 863, 2019, pp. 50–875). In agreement with these findings, the nonlinear lower-branch travelling-wave solution analysed here, which is believed to mediate transition to turbulence in isothermal pipe flow, is shown to be suppressed by buoyancy. A linear instability of the laminar base flow is responsible for the appearance of the relatively quiescent convection driven state for 𝐶≳4 across the range of Reynolds numbers considered. In the suppression of turbulence, however, i.e. in the transition from turbulence, we find clearer association with the analysis of He et al. (J. Fluid Mech., vol. 809, 2016, pp. 31–71) than with the above dynamical systems approach, which describes better the transition to turbulence. The laminarisation criterion He et al. propose, based on an apparent Reynolds number of the flow as measured by its driving pressure gradient, is found to capture the critical 𝐶=𝐶𝑐𝑟(𝑅𝑒) above which the flow will be laminarised or switch to the convection-driven type. Our analysis suggests that it is the weakened rolls, rather than the streaks, which appear to be critical for laminarisation."}],"oa_version":"Published Version","scopus_import":"1","month":"07","intvolume":" 919","citation":{"apa":"Marensi, E., He, S., & Willis, A. P. (2021). Suppression of turbulence and travelling waves in a vertical heated pipe. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2021.371","ama":"Marensi E, He S, Willis AP. Suppression of turbulence and travelling waves in a vertical heated pipe. Journal of Fluid Mechanics. 2021;919. doi:10.1017/jfm.2021.371","ieee":"E. Marensi, S. He, and A. P. Willis, “Suppression of turbulence and travelling waves in a vertical heated pipe,” Journal of Fluid Mechanics, vol. 919. Cambridge University Press, 2021.","short":"E. Marensi, S. He, A.P. Willis, Journal of Fluid Mechanics 919 (2021).","mla":"Marensi, Elena, et al. “Suppression of Turbulence and Travelling Waves in a Vertical Heated Pipe.” Journal of Fluid Mechanics, vol. 919, A17, Cambridge University Press, 2021, doi:10.1017/jfm.2021.371.","ista":"Marensi E, He S, Willis AP. 2021. Suppression of turbulence and travelling waves in a vertical heated pipe. Journal of Fluid Mechanics. 919, A17.","chicago":"Marensi, Elena, Shuisheng He, and Ashley P. Willis. “Suppression of Turbulence and Travelling Waves in a Vertical Heated Pipe.” Journal of Fluid Mechanics. Cambridge University Press, 2021. https://doi.org/10.1017/jfm.2021.371."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","author":[{"first_name":"Elena","id":"0BE7553A-1004-11EA-B805-18983DDC885E","full_name":"Marensi, Elena","last_name":"Marensi"},{"last_name":"He","full_name":"He, Shuisheng","first_name":"Shuisheng"},{"first_name":"Ashley P.","full_name":"Willis, Ashley P.","last_name":"Willis"}],"external_id":{"arxiv":["2008.13486"],"isi":["000653785000001"]},"article_processing_charge":"Yes (via OA deal)","title":"Suppression of turbulence and travelling waves in a vertical heated pipe","article_number":"A17","isi":1,"has_accepted_license":"1","year":"2021","day":"25","publication":"Journal of Fluid Mechanics","date_published":"2021-07-25T00:00:00Z","doi":"10.1017/jfm.2021.371","date_created":"2021-06-06T22:01:30Z","acknowledgement":"The anonymous referees are kindly acknowledged for their useful suggestions andcomments.","quality_controlled":"1","publisher":"Cambridge University Press","oa":1},{"isi":1,"year":"2021","day":"18","publication":"Physical Review Letters","doi":"10.1103/PhysRevLett.126.244502","date_published":"2021-06-18T00:00:00Z","date_created":"2021-06-16T15:45:36Z","acknowledgement":"We thank the referees for improving this Letter with their comments. We acknowledge stimulating discussions with\r\nH. Edelsbrunner. This work was supported by Grant No. 662960 from the Simons Foundation (B. H.). The numerical calculations were performed at TUBITAK ULAKBIM High Performance and Grid Computing Center (TRUBA resources) and IST Austria High Performance Computing cluster.","quality_controlled":"1","publisher":"American Physical Society","oa":1,"citation":{"chicago":"Yalniz, Gökhan, Björn Hof, and Nazmi B Budanur. “Coarse Graining the State Space of a Turbulent Flow Using Periodic Orbits.” Physical Review Letters. American Physical Society, 2021. https://doi.org/10.1103/PhysRevLett.126.244502.","ista":"Yalniz G, Hof B, Budanur NB. 2021. Coarse graining the state space of a turbulent flow using periodic orbits. Physical Review Letters. 126(24), 244502.","mla":"Yalniz, Gökhan, et al. “Coarse Graining the State Space of a Turbulent Flow Using Periodic Orbits.” Physical Review Letters, vol. 126, no. 24, 244502, American Physical Society, 2021, doi:10.1103/PhysRevLett.126.244502.","short":"G. Yalniz, B. Hof, N.B. Budanur, Physical Review Letters 126 (2021).","ieee":"G. Yalniz, B. Hof, and N. B. Budanur, “Coarse graining the state space of a turbulent flow using periodic orbits,” Physical Review Letters, vol. 126, no. 24. American Physical Society, 2021.","ama":"Yalniz G, Hof B, Budanur NB. Coarse graining the state space of a turbulent flow using periodic orbits. Physical Review Letters. 2021;126(24). doi:10.1103/PhysRevLett.126.244502","apa":"Yalniz, G., Hof, B., & Budanur, N. B. (2021). Coarse graining the state space of a turbulent flow using periodic orbits. Physical Review Letters. American Physical Society. https://doi.org/10.1103/PhysRevLett.126.244502"},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","author":[{"id":"66E74FA2-D8BF-11E9-8249-8DE2E5697425","first_name":"Gökhan","orcid":"0000-0002-8490-9312","full_name":"Yalniz, Gökhan","last_name":"Yalniz"},{"last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn"},{"last_name":"Budanur","full_name":"Budanur, Nazmi B","orcid":"0000-0003-0423-5010","first_name":"Nazmi B","id":"3EA1010E-F248-11E8-B48F-1D18A9856A87"}],"article_processing_charge":"No","external_id":{"arxiv":["2007.02584"],"isi":["000663310100008"]},"title":"Coarse graining the state space of a turbulent flow using periodic orbits","article_number":"244502","project":[{"grant_number":"662960","name":"Revisiting the Turbulence Problem Using Statistical Mechanics: Experimental Studies on Transitional and Turbulent Flows","_id":"238598C6-32DE-11EA-91FC-C7463DDC885E"}],"publication_identifier":{"issn":["0031-9007"],"eissn":["1079-7114"]},"publication_status":"published","language":[{"iso":"eng"}],"issue":"24","related_material":{"link":[{"description":"News on IST Homepage","relation":"press_release","url":"https://ist.ac.at/en/news/turbulent-flow-simplified/"}]},"volume":126,"acknowledged_ssus":[{"_id":"ScienComp"}],"abstract":[{"lang":"eng","text":"We show that turbulent dynamics that arise in simulations of the three-dimensional Navier--Stokes equations in a triply-periodic domain under sinusoidal forcing can be described as transient visits to the neighborhoods of unstable time-periodic solutions. Based on this description, we reduce the original system with more than 10^5 degrees of freedom to a 17-node Markov chain where each node corresponds to the neighborhood of a periodic orbit. The model accurately reproduces long-term averages of the system's observables as weighted sums over the periodic orbits.\r\n"}],"oa_version":"Preprint","main_file_link":[{"url":"https://arxiv.org/abs/2007.02584","open_access":"1"}],"month":"06","intvolume":" 126","date_updated":"2023-08-08T14:08:36Z","department":[{"_id":"GradSch"},{"_id":"BjHo"}],"_id":"9558","type":"journal_article","article_type":"letter_note","status":"public"},{"ddc":["530"],"date_updated":"2023-08-14T08:12:12Z","file_date_updated":"2021-11-03T11:31:24Z","department":[{"_id":"BjHo"}],"_id":"10203","status":"public","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"article_type":"original","type":"journal_article","language":[{"iso":"eng"}],"file":[{"checksum":"8580d128389860f732028c521cd5949e","file_id":"10212","success":1,"access_level":"open_access","relation":"main_file","content_type":"application/pdf","date_created":"2021-11-03T11:31:24Z","file_name":"2021_NatComm_Sortino.pdf","creator":"cchlebak","date_updated":"2021-11-03T11:31:24Z","file_size":1434201}],"publication_status":"published","publication_identifier":{"eissn":["2041-1723"]},"volume":12,"oa_version":"Published Version","abstract":[{"text":"Single photon emitters in atomically-thin semiconductors can be deterministically positioned using strain induced by underlying nano-structures. Here, we couple monolayer WSe2 to high-refractive-index gallium phosphide dielectric nano-antennas providing both optical enhancement and monolayer deformation. For single photon emitters formed on such nano-antennas, we find very low (femto-Joule) saturation pulse energies and up to 104 times brighter photoluminescence than in WSe2 placed on low-refractive-index SiO2 pillars. We show that the key to these observations is the increase on average by a factor of 5 of the quantum efficiency of the emitters coupled to the nano-antennas. This further allows us to gain new insights into their photoluminescence dynamics, revealing the roles of the dark exciton reservoir and Auger processes. We also find that the coherence time of such emitters is limited by intrinsic dephasing processes. Our work establishes dielectric nano-antennas as a platform for high-efficiency quantum light generation in monolayer semiconductors.","lang":"eng"}],"intvolume":" 12","month":"10","scopus_import":"1","user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"mla":"Sortino, Luca, et al. “Bright Single Photon Emitters with Enhanced Quantum Efficiency in a Two-Dimensional Semiconductor Coupled with Dielectric Nano-Antennas.” Nature Communications, vol. 12, 6063, Springer Nature, 2021, doi:10.1038/s41467-021-26262-3.","short":"L. Sortino, P.G. Zotev, C.L. Phillips, A.J. Brash, J. Cambiasso, E. Marensi, A.M. Fox, S.A. Maier, R. Sapienza, A.I. Tartakovskii, Nature Communications 12 (2021).","ieee":"L. Sortino et al., “Bright single photon emitters with enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric nano-antennas,” Nature Communications, vol. 12. Springer Nature, 2021.","apa":"Sortino, L., Zotev, P. G., Phillips, C. L., Brash, A. J., Cambiasso, J., Marensi, E., … Tartakovskii, A. I. (2021). Bright single photon emitters with enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric nano-antennas. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-021-26262-3","ama":"Sortino L, Zotev PG, Phillips CL, et al. Bright single photon emitters with enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric nano-antennas. Nature Communications. 2021;12. doi:10.1038/s41467-021-26262-3","chicago":"Sortino, Luca, Panaiot G. Zotev, Catherine L. Phillips, Alistair J. Brash, Javier Cambiasso, Elena Marensi, A. Mark Fox, Stefan A. Maier, Riccardo Sapienza, and Alexander I. Tartakovskii. “Bright Single Photon Emitters with Enhanced Quantum Efficiency in a Two-Dimensional Semiconductor Coupled with Dielectric Nano-Antennas.” Nature Communications. Springer Nature, 2021. https://doi.org/10.1038/s41467-021-26262-3.","ista":"Sortino L, Zotev PG, Phillips CL, Brash AJ, Cambiasso J, Marensi E, Fox AM, Maier SA, Sapienza R, Tartakovskii AI. 2021. Bright single photon emitters with enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric nano-antennas. Nature Communications. 12, 6063."},"title":"Bright single photon emitters with enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric nano-antennas","external_id":{"arxiv":["2103.16986"],"isi":["000708601800015"]},"article_processing_charge":"No","author":[{"full_name":"Sortino, Luca","last_name":"Sortino","first_name":"Luca"},{"first_name":"Panaiot G.","last_name":"Zotev","full_name":"Zotev, Panaiot G."},{"first_name":"Catherine L.","full_name":"Phillips, Catherine L.","last_name":"Phillips"},{"first_name":"Alistair J.","full_name":"Brash, Alistair J.","last_name":"Brash"},{"full_name":"Cambiasso, Javier","last_name":"Cambiasso","first_name":"Javier"},{"id":"0BE7553A-1004-11EA-B805-18983DDC885E","first_name":"Elena","orcid":"0000-0001-7173-4923","full_name":"Marensi, Elena","last_name":"Marensi"},{"full_name":"Fox, A. Mark","last_name":"Fox","first_name":"A. Mark"},{"first_name":"Stefan A.","last_name":"Maier","full_name":"Maier, Stefan A."},{"full_name":"Sapienza, Riccardo","last_name":"Sapienza","first_name":"Riccardo"},{"last_name":"Tartakovskii","full_name":"Tartakovskii, Alexander I.","first_name":"Alexander I."}],"article_number":"6063","publication":"Nature Communications","day":"18","year":"2021","has_accepted_license":"1","isi":1,"date_created":"2021-10-31T23:01:30Z","date_published":"2021-10-18T00:00:00Z","doi":"10.1038/s41467-021-26262-3","acknowledgement":"L.S., P.G.Z., and A.I.T. thank the financial support of the European Graphene Flagship Project under grant agreements 881603 and EPSRC grant EP/S030751/1. L.S. and A.I.T. thank the European Union’s Horizon 2020 research and innovation programme under ITN Spin-NANO Marie Sklodowska-Curie grant agreement no. 676108. P.G.Z. and A.I.T. thank the European Union’s Horizon 2020 research and innovation programme under ITN 4PHOTON Marie Sklodowska-Curie grant agreement no. 721394. J.C., S.A.M., and R.S. acknowledge funding by EPSRC (EP/P033369 and EP/M013812). C.L.P., A.J.B., A.I.T., and A.M.F. acknowledge funding by EPSRC Programme Grant EP/N031776/1. S.A.M. acknowledges the Lee-Lucas Chair in Physics, the Solar Energies go Hybrid (SolTech) programme, and the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy - EXC 2089/1 - 390776260.","oa":1,"quality_controlled":"1","publisher":"Springer Nature"},{"author":[{"first_name":"George H","id":"448BD5BC-F248-11E8-B48F-1D18A9856A87","full_name":"Choueiri, George H","last_name":"Choueiri"},{"last_name":"Lopez Alonso","orcid":"0000-0002-0384-2022","full_name":"Lopez Alonso, Jose M","id":"40770848-F248-11E8-B48F-1D18A9856A87","first_name":"Jose M"},{"first_name":"Atul","id":"2A2006B2-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0002-3072-5999","full_name":"Varshney, Atul","last_name":"Varshney"},{"first_name":"Sarath","full_name":"Sankar, Sarath","last_name":"Sankar"},{"last_name":"Hof","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn"}],"article_processing_charge":"No","external_id":{"arxiv":["2103.00023"],"isi":["000720926900019"],"pmid":[" 34732570"]},"title":"Experimental observation of the origin and structure of elastoinertial turbulence","citation":{"short":"G.H. Choueiri, J.M. Lopez Alonso, A. Varshney, S. Sankar, B. Hof, Proceedings of the National Academy of Sciences 118 (2021).","ieee":"G. H. Choueiri, J. M. Lopez Alonso, A. Varshney, S. Sankar, and B. Hof, “Experimental observation of the origin and structure of elastoinertial turbulence,” Proceedings of the National Academy of Sciences, vol. 118, no. 45. National Academy of Sciences, 2021.","ama":"Choueiri GH, Lopez Alonso JM, Varshney A, Sankar S, Hof B. Experimental observation of the origin and structure of elastoinertial turbulence. Proceedings of the National Academy of Sciences. 2021;118(45). doi:10.1073/pnas.2102350118","apa":"Choueiri, G. H., Lopez Alonso, J. M., Varshney, A., Sankar, S., & Hof, B. (2021). Experimental observation of the origin and structure of elastoinertial turbulence. Proceedings of the National Academy of Sciences. National Academy of Sciences. https://doi.org/10.1073/pnas.2102350118","mla":"Choueiri, George H., et al. “Experimental Observation of the Origin and Structure of Elastoinertial Turbulence.” Proceedings of the National Academy of Sciences, vol. 118, no. 45, e2102350118, National Academy of Sciences, 2021, doi:10.1073/pnas.2102350118.","ista":"Choueiri GH, Lopez Alonso JM, Varshney A, Sankar S, Hof B. 2021. Experimental observation of the origin and structure of elastoinertial turbulence. Proceedings of the National Academy of Sciences. 118(45), e2102350118.","chicago":"Choueiri, George H, Jose M Lopez Alonso, Atul Varshney, Sarath Sankar, and Björn Hof. “Experimental Observation of the Origin and Structure of Elastoinertial Turbulence.” Proceedings of the National Academy of Sciences. National Academy of Sciences, 2021. https://doi.org/10.1073/pnas.2102350118."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","project":[{"_id":"238B8092-32DE-11EA-91FC-C7463DDC885E","call_identifier":"FWF","name":"Instabilities in pulsating pipe flow of Newtonian and complex fluids","grant_number":"I04188"}],"article_number":"e2102350118","doi":"10.1073/pnas.2102350118","date_published":"2021-11-03T00:00:00Z","date_created":"2021-11-17T13:24:24Z","isi":1,"year":"2021","day":"03","publication":"Proceedings of the National Academy of Sciences","quality_controlled":"1","publisher":"National Academy of Sciences","oa":1,"acknowledgement":"We thank Y. Dubief, R. Kerswell, E. Marensi, V. Shankar, V. Steinberg, and V. Terrapon for discussions and helpful comments. A.V. and B.H. acknowledge funding from the Austrian Science Fund, grant I4188-N30, within the Deutsche Forschungsgemeinschaft research unit FOR 2688.","department":[{"_id":"BjHo"}],"date_updated":"2023-08-14T11:50:10Z","type":"journal_article","article_type":"original","status":"public","keyword":["multidisciplinary","elastoinertial turbulence","viscoelastic flows","elastic instability","drag reduction"],"_id":"10299","volume":118,"issue":"45","publication_identifier":{"eissn":["1091-6490"],"issn":["0027-8424"]},"publication_status":"published","language":[{"iso":"eng"}],"scopus_import":"1","main_file_link":[{"url":"https://arxiv.org/abs/2103.00023","open_access":"1"}],"month":"11","intvolume":" 118","abstract":[{"lang":"eng","text":"Turbulence generally arises in shear flows if velocities and hence, inertial forces are sufficiently large. In striking contrast, viscoelastic fluids can exhibit disordered motion even at vanishing inertia. Intermediate between these cases, a state of chaotic motion, “elastoinertial turbulence” (EIT), has been observed in a narrow Reynolds number interval. We here determine the origin of EIT in experiments and show that characteristic EIT structures can be detected across an unexpectedly wide range of parameters. Close to onset, a pattern of chevron-shaped streaks emerges in qualitative agreement with linear and weakly nonlinear theory. However, in experiments, the dynamics remain weakly chaotic, and the instability can be traced to far lower Reynolds numbers than permitted by theory. For increasing inertia, the flow undergoes a transformation to a wall mode composed of inclined near-wall streaks and shear layers. This mode persists to what is known as the “maximum drag reduction limit,” and overall EIT is found to dominate viscoelastic flows across more than three orders of magnitude in Reynolds number."}],"oa_version":"Preprint","pmid":1},{"day":"29","has_accepted_license":"1","year":"2021","doi":"10.15479/at:ista:9728","date_published":"2021-07-29T00:00:00Z","date_created":"2021-07-27T13:40:30Z","page":"118","publisher":"Institute of Science and Technology Austria","oa":1,"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"short":"N. Agrawal, Transition to Turbulence and Drag Reduction in Particle-Laden Pipe Flows, Institute of Science and Technology Austria, 2021.","ieee":"N. Agrawal, “Transition to turbulence and drag reduction in particle-laden pipe flows,” Institute of Science and Technology Austria, 2021.","apa":"Agrawal, N. (2021). Transition to turbulence and drag reduction in particle-laden pipe flows. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:9728","ama":"Agrawal N. Transition to turbulence and drag reduction in particle-laden pipe flows. 2021. doi:10.15479/at:ista:9728","mla":"Agrawal, Nishchal. Transition to Turbulence and Drag Reduction in Particle-Laden Pipe Flows. Institute of Science and Technology Austria, 2021, doi:10.15479/at:ista:9728.","ista":"Agrawal N. 2021. Transition to turbulence and drag reduction in particle-laden pipe flows. Institute of Science and Technology Austria.","chicago":"Agrawal, Nishchal. “Transition to Turbulence and Drag Reduction in Particle-Laden Pipe Flows.” Institute of Science and Technology Austria, 2021. https://doi.org/10.15479/at:ista:9728."},"title":"Transition to turbulence and drag reduction in particle-laden pipe flows","author":[{"id":"469E6004-F248-11E8-B48F-1D18A9856A87","first_name":"Nishchal","full_name":"Agrawal, Nishchal","last_name":"Agrawal"}],"article_processing_charge":"No","file":[{"file_name":"Transition to Turbulence and Drag Reduction in Particle-Laden Pipe Flows.zip","date_created":"2021-07-28T13:32:02Z","creator":"nagrawal","file_size":22859658,"date_updated":"2022-07-29T22:30:05Z","file_id":"9744","checksum":"77436be3563a90435024307b1b5ee7e8","relation":"source_file","access_level":"closed","embargo_to":"open_access","content_type":"application/x-zip-compressed"},{"date_created":"2021-07-28T13:32:05Z","file_name":"Transition to Turbulence and Drag Reduction in Particle-Laden Pipe Flows.pdf","date_updated":"2022-07-29T22:30:05Z","file_size":18658048,"creator":"nagrawal","file_id":"9745","checksum":"72a891d7daba85445c29b868c22575ed","embargo":"2022-07-28","content_type":"application/pdf","access_level":"open_access","relation":"main_file"}],"language":[{"iso":"eng"}],"publication_identifier":{"issn":["2663-337X"]},"publication_status":"published","degree_awarded":"PhD","related_material":{"record":[{"status":"public","id":"6189","relation":"part_of_dissertation"}]},"oa_version":"Published Version","abstract":[{"text":"Most real-world flows are multiphase, yet we know little about them compared to their single-phase counterparts. Multiphase flows are more difficult to investigate as their dynamics occur in large parameter space and involve complex phenomena such as preferential concentration, turbulence modulation, non-Newtonian rheology, etc. Over the last few decades, experiments in particle-laden flows have taken a back seat in favour of ever-improving computational resources. However, computers are still not powerful enough to simulate a real-world fluid with millions of finite-size particles. Experiments are essential not only because they offer a reliable way to investigate real-world multiphase flows but also because they serve to validate numerical studies and steer the research in a relevant direction. In this work, we have experimentally investigated particle-laden flows in pipes, and in particular, examined the effect of particles on the laminar-turbulent transition and the drag scaling in turbulent flows.\r\n\r\nFor particle-laden pipe flows, an earlier study [Matas et al., 2003] reported how the sub-critical (i.e., hysteretic) transition that occurs via localised turbulent structures called puffs is affected by the addition of particles. In this study, in addition to this known transition, we found a super-critical transition to a globally fluctuating state with increasing particle concentration. At the same time, the Newtonian-type transition via puffs is delayed to larger Reynolds numbers. At an even higher concentration, only the globally fluctuating state is found. The dynamics of particle-laden flows are hence determined by two competing instabilities that give rise to three flow regimes: Newtonian-type turbulence at low, a particle-induced globally fluctuating state at high, and a coexistence state at intermediate concentrations.\r\n\r\nThe effect of particles on turbulent drag is ambiguous, with studies reporting drag reduction, no net change, and even drag increase. The ambiguity arises because, in addition to particle concentration, particle shape, size, and density also affect the net drag. Even similar particles might affect the flow dissimilarly in different Reynolds number and concentration ranges. In the present study, we explored a wide range of both Reynolds number and concentration, using spherical as well as cylindrical particles. We found that the spherical particles do not reduce drag while the cylindrical particles are drag-reducing within a specific Reynolds number interval. The interval strongly depends on the particle concentration and the relative size of the pipe and particles. Within this interval, the magnitude of drag reduction reaches a maximum. These drag reduction maxima appear to fall onto a distinct power-law curve irrespective of the pipe diameter and particle concentration, and this curve can be considered as the maximum drag reduction asymptote for a given fibre shape. Such an asymptote is well known for polymeric flows but had not been identified for particle-laden flows prior to this work.","lang":"eng"}],"acknowledged_ssus":[{"_id":"M-Shop"}],"month":"07","alternative_title":["ISTA Thesis"],"ddc":["532"],"supervisor":[{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754"}],"date_updated":"2024-02-28T13:14:39Z","department":[{"_id":"GradSch"},{"_id":"BjHo"}],"file_date_updated":"2022-07-29T22:30:05Z","_id":"9728","status":"public","keyword":["Drag Reduction","Transition to Turbulence","Multiphase Flows","particle Laden Flows","Complex Flows","Experiments","Fluid Dynamics"],"type":"dissertation","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"}},{"oa":1,"quality_controlled":"1","publisher":"Elsevier","date_created":"2020-01-26T23:00:35Z","date_published":"2020-01-17T00:00:00Z","doi":"10.1016/j.softx.2019.100395","year":"2020","has_accepted_license":"1","isi":1,"publication":"SoftwareX","day":"17","article_number":"100395","external_id":{"isi":["000552271200011"],"arxiv":["1908.00587"]},"article_processing_charge":"No","author":[{"orcid":"0000-0002-0384-2022","full_name":"Lopez Alonso, Jose M","last_name":"Lopez Alonso","first_name":"Jose M","id":"40770848-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Daniel","last_name":"Feldmann","full_name":"Feldmann, Daniel"},{"first_name":"Markus","last_name":"Rampp","full_name":"Rampp, Markus"},{"first_name":"Alberto","last_name":"Vela-Martín","full_name":"Vela-Martín, Alberto"},{"id":"374A3F1A-F248-11E8-B48F-1D18A9856A87","first_name":"Liang","last_name":"Shi","full_name":"Shi, Liang"},{"first_name":"Marc","last_name":"Avila","full_name":"Avila, Marc"}],"title":"nsCouette – A high-performance code for direct numerical simulations of turbulent Taylor–Couette flow","citation":{"ista":"Lopez Alonso JM, Feldmann D, Rampp M, Vela-Martín A, Shi L, Avila M. 2020. nsCouette – A high-performance code for direct numerical simulations of turbulent Taylor–Couette flow. SoftwareX. 11, 100395.","chicago":"Lopez Alonso, Jose M, Daniel Feldmann, Markus Rampp, Alberto Vela-Martín, Liang Shi, and Marc Avila. “NsCouette – A High-Performance Code for Direct Numerical Simulations of Turbulent Taylor–Couette Flow.” SoftwareX. Elsevier, 2020. https://doi.org/10.1016/j.softx.2019.100395.","ieee":"J. M. Lopez Alonso, D. Feldmann, M. Rampp, A. Vela-Martín, L. Shi, and M. Avila, “nsCouette – A high-performance code for direct numerical simulations of turbulent Taylor–Couette flow,” SoftwareX, vol. 11. Elsevier, 2020.","short":"J.M. Lopez Alonso, D. Feldmann, M. Rampp, A. Vela-Martín, L. Shi, M. Avila, SoftwareX 11 (2020).","apa":"Lopez Alonso, J. M., Feldmann, D., Rampp, M., Vela-Martín, A., Shi, L., & Avila, M. (2020). nsCouette – A high-performance code for direct numerical simulations of turbulent Taylor–Couette flow. SoftwareX. Elsevier. https://doi.org/10.1016/j.softx.2019.100395","ama":"Lopez Alonso JM, Feldmann D, Rampp M, Vela-Martín A, Shi L, Avila M. nsCouette – A high-performance code for direct numerical simulations of turbulent Taylor–Couette flow. SoftwareX. 2020;11. doi:10.1016/j.softx.2019.100395","mla":"Lopez Alonso, Jose M., et al. “NsCouette – A High-Performance Code for Direct Numerical Simulations of Turbulent Taylor–Couette Flow.” SoftwareX, vol. 11, 100395, Elsevier, 2020, doi:10.1016/j.softx.2019.100395."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","scopus_import":"1","intvolume":" 11","month":"01","abstract":[{"lang":"eng","text":"We present nsCouette, a highly scalable software tool to solve the Navier–Stokes equations for incompressible fluid flow between differentially heated and independently rotating, concentric cylinders. It is based on a pseudospectral spatial discretization and dynamic time-stepping. It is implemented in modern Fortran with a hybrid MPI-OpenMP parallelization scheme and thus designed to compute turbulent flows at high Reynolds and Rayleigh numbers. An additional GPU implementation (C-CUDA) for intermediate problem sizes and a version for pipe flow (nsPipe) are also provided."}],"oa_version":"Published Version","volume":11,"publication_status":"published","publication_identifier":{"eissn":["23527110"]},"language":[{"iso":"eng"}],"file":[{"file_id":"7365","checksum":"2af1a1a3cc33557b345145276f221668","content_type":"application/pdf","access_level":"open_access","relation":"main_file","date_created":"2020-01-27T07:32:46Z","file_name":"2020_SoftwareX_Lopez.pdf","date_updated":"2020-07-14T12:47:56Z","file_size":679707,"creator":"dernst"}],"tmp":{"short":"CC BY-NC-ND (4.0)","name":"Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)","legal_code_url":"https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode","image":"/images/cc_by_nc_nd.png"},"type":"journal_article","article_type":"original","status":"public","_id":"7364","file_date_updated":"2020-07-14T12:47:56Z","department":[{"_id":"BjHo"}],"date_updated":"2023-08-17T14:29:59Z","ddc":["000"]},{"article_number":"023903","citation":{"chicago":"Budanur, Nazmi B, Elena Marensi, Ashley P. Willis, and Björn Hof. “Upper Edge of Chaos and the Energetics of Transition in Pipe Flow.” Physical Review Fluids. American Physical Society, 2020. https://doi.org/10.1103/physrevfluids.5.023903.","ista":"Budanur NB, Marensi E, Willis AP, Hof B. 2020. Upper edge of chaos and the energetics of transition in pipe flow. Physical Review Fluids. 5(2), 023903.","mla":"Budanur, Nazmi B., et al. “Upper Edge of Chaos and the Energetics of Transition in Pipe Flow.” Physical Review Fluids, vol. 5, no. 2, 023903, American Physical Society, 2020, doi:10.1103/physrevfluids.5.023903.","ieee":"N. B. Budanur, E. Marensi, A. P. Willis, and B. Hof, “Upper edge of chaos and the energetics of transition in pipe flow,” Physical Review Fluids, vol. 5, no. 2. American Physical Society, 2020.","short":"N.B. Budanur, E. Marensi, A.P. Willis, B. Hof, Physical Review Fluids 5 (2020).","apa":"Budanur, N. B., Marensi, E., Willis, A. P., & Hof, B. (2020). Upper edge of chaos and the energetics of transition in pipe flow. Physical Review Fluids. American Physical Society. https://doi.org/10.1103/physrevfluids.5.023903","ama":"Budanur NB, Marensi E, Willis AP, Hof B. Upper edge of chaos and the energetics of transition in pipe flow. Physical Review Fluids. 2020;5(2). doi:10.1103/physrevfluids.5.023903"},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","author":[{"last_name":"Budanur","orcid":"0000-0003-0423-5010","full_name":"Budanur, Nazmi B","first_name":"Nazmi B","id":"3EA1010E-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Elena","full_name":"Marensi, Elena","last_name":"Marensi"},{"last_name":"Willis","full_name":"Willis, Ashley P.","first_name":"Ashley P."},{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754"}],"external_id":{"arxiv":["1912.09270"],"isi":["000515065100001"]},"article_processing_charge":"No","title":"Upper edge of chaos and the energetics of transition in pipe flow","publisher":"American Physical Society","quality_controlled":"1","oa":1,"isi":1,"year":"2020","day":"21","publication":"Physical Review Fluids","doi":"10.1103/physrevfluids.5.023903","date_published":"2020-02-21T00:00:00Z","date_created":"2020-02-27T10:26:57Z","_id":"7534","article_type":"original","type":"journal_article","status":"public","date_updated":"2023-08-18T06:44:46Z","department":[{"_id":"BjHo"}],"abstract":[{"lang":"eng","text":"In the past two decades, our understanding of the transition to turbulence in shear flows with linearly stable laminar solutions has greatly improved. Regarding the susceptibility of the laminar flow, two concepts have been particularly useful: the edge states and the minimal seeds. In this nonlinear picture of the transition, the basin boundary of turbulence is set by the edge state's stable manifold and this manifold comes closest in energy to the laminar equilibrium at the minimal seed. We begin this paper by presenting numerical experiments in which three-dimensional perturbations are too energetic to trigger turbulence in pipe flow but they do lead to turbulence when their amplitude is reduced. We show that this seemingly counterintuitive observation is in fact consistent with the fully nonlinear description of the transition mediated by the edge state. In order to understand the physical mechanisms behind this process, we measure the turbulent kinetic energy production and dissipation rates as a function of the radial coordinate. Our main observation is that the transition to turbulence relies on the energy amplification away from the wall, as opposed to the turbulence itself, whose energy is predominantly produced near the wall. This observation is further supported by the similar analyses on the minimal seeds and the edge states. Furthermore, we show that the time evolution of production-over-dissipation curves provides a clear distinction between the different initial amplification stages of the transition to turbulence from the minimal seed."}],"oa_version":"Preprint","scopus_import":"1","main_file_link":[{"url":"https://arxiv.org/abs/1912.09270","open_access":"1"}],"month":"02","intvolume":" 5","publication_identifier":{"issn":["2469-990X"]},"publication_status":"published","language":[{"iso":"eng"}],"issue":"2","volume":5},{"volume":30,"issue":"3","publication_status":"published","publication_identifier":{"issn":["1054-1500"],"eissn":["1089-7682"]},"language":[{"iso":"eng"}],"main_file_link":[{"url":"https://doi.org/10.1063/1.5122969","open_access":"1"}],"scopus_import":"1","intvolume":" 30","month":"03","abstract":[{"lang":"eng","text":"We introduce “state space persistence analysis” for deducing the symbolic dynamics of time series data obtained from high-dimensional chaotic attractors. To this end, we adapt a topological data analysis technique known as persistent homology for the characterization of state space projections of chaotic trajectories and periodic orbits. By comparing the shapes along a chaotic trajectory to those of the periodic orbits, state space persistence analysis quantifies the shape similarity of chaotic trajectory segments and periodic orbits. We demonstrate the method by applying it to the three-dimensional Rössler system and a 30-dimensional discretization of the Kuramoto–Sivashinsky partial differential equation in (1+1) dimensions.\r\nOne way of studying chaotic attractors systematically is through their symbolic dynamics, in which one partitions the state space into qualitatively different regions and assigns a symbol to each such region.1–3 This yields a “coarse-grained” state space of the system, which can then be reduced to a Markov chain encoding all possible transitions between the states of the system. While it is possible to obtain the symbolic dynamics of low-dimensional chaotic systems with standard tools such as Poincaré maps, when applied to high-dimensional systems such as turbulent flows, these tools alone are not sufficient to determine symbolic dynamics.4,5 In this paper, we develop “state space persistence analysis” and demonstrate that it can be utilized to infer the symbolic dynamics in very high-dimensional settings."}],"oa_version":"Published Version","department":[{"_id":"BjHo"}],"date_updated":"2023-08-18T06:47:16Z","type":"journal_article","article_type":"original","status":"public","_id":"7563","date_created":"2020-03-04T08:06:25Z","doi":"10.1063/1.5122969","date_published":"2020-03-03T00:00:00Z","year":"2020","isi":1,"publication":"Chaos","day":"03","oa":1,"quality_controlled":"1","publisher":"AIP Publishing","external_id":{"arxiv":["1910.04584"],"isi":["000519254800002"]},"article_processing_charge":"No","author":[{"last_name":"Yalniz","full_name":"Yalniz, Gökhan","orcid":"0000-0002-8490-9312","id":"66E74FA2-D8BF-11E9-8249-8DE2E5697425","first_name":"Gökhan"},{"last_name":"Budanur","full_name":"Budanur, Nazmi B","orcid":"0000-0003-0423-5010","first_name":"Nazmi B","id":"3EA1010E-F248-11E8-B48F-1D18A9856A87"}],"title":"Inferring symbolic dynamics of chaotic flows from persistence","citation":{"mla":"Yalniz, Gökhan, and Nazmi B. Budanur. “Inferring Symbolic Dynamics of Chaotic Flows from Persistence.” Chaos, vol. 30, no. 3, 033109, AIP Publishing, 2020, doi:10.1063/1.5122969.","apa":"Yalniz, G., & Budanur, N. B. (2020). Inferring symbolic dynamics of chaotic flows from persistence. Chaos. AIP Publishing. https://doi.org/10.1063/1.5122969","ama":"Yalniz G, Budanur NB. Inferring symbolic dynamics of chaotic flows from persistence. Chaos. 2020;30(3). doi:10.1063/1.5122969","ieee":"G. Yalniz and N. B. Budanur, “Inferring symbolic dynamics of chaotic flows from persistence,” Chaos, vol. 30, no. 3. AIP Publishing, 2020.","short":"G. Yalniz, N.B. Budanur, Chaos 30 (2020).","chicago":"Yalniz, Gökhan, and Nazmi B Budanur. “Inferring Symbolic Dynamics of Chaotic Flows from Persistence.” Chaos. AIP Publishing, 2020. https://doi.org/10.1063/1.5122969.","ista":"Yalniz G, Budanur NB. 2020. Inferring symbolic dynamics of chaotic flows from persistence. Chaos. 30(3), 033109."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","article_number":"033109"},{"_id":"8043","status":"public","type":"journal_article","article_type":"original","tmp":{"name":"Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)","image":"/images/cc_by_nc_sa.png","legal_code_url":"https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode","short":"CC BY-NC-SA (4.0)"},"ddc":["530"],"date_updated":"2023-08-22T07:48:02Z","file_date_updated":"2020-07-14T12:48:08Z","department":[{"_id":"BjHo"}],"oa_version":"Published Version","abstract":[{"text":"With decreasing Reynolds number, Re, turbulence in channel flow becomes spatio-temporally intermittent and self-organises into solitary stripes oblique to the mean flow direction. We report here the existence of localised nonlinear travelling wave solutions of the Navier–Stokes equations possessing this obliqueness property. Such solutions are identified numerically using edge tracking coupled with arclength continuation. All solutions emerge in saddle-node bifurcations at values of Re lower than the non-localised solutions. Relative periodic orbit solutions bifurcating from branches of travelling waves have also been computed. A complete parametric study is performed, including their stability, the investigation of their large-scale flow, and the robustness to changes of the numerical domain.","lang":"eng"}],"month":"08","intvolume":" 897","scopus_import":"1","file":[{"access_level":"open_access","relation":"main_file","content_type":"application/pdf","checksum":"3f487bf6d9286787096306eaa18702e8","file_id":"8070","creator":"cziletti","date_updated":"2020-07-14T12:48:08Z","file_size":767873,"date_created":"2020-06-30T08:37:37Z","file_name":"2020_JournalOfFluidMech_Paranjape.pdf"}],"language":[{"iso":"eng"}],"publication_identifier":{"issn":["00221120"],"eissn":["14697645"]},"publication_status":"published","volume":897,"license":"https://creativecommons.org/licenses/by-nc-sa/4.0/","article_number":"A7","user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"ama":"Paranjape CS, Duguet Y, Hof B. Oblique stripe solutions of channel flow. Journal of Fluid Mechanics. 2020;897. doi:10.1017/jfm.2020.322","apa":"Paranjape, C. S., Duguet, Y., & Hof, B. (2020). Oblique stripe solutions of channel flow. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2020.322","ieee":"C. S. Paranjape, Y. Duguet, and B. Hof, “Oblique stripe solutions of channel flow,” Journal of Fluid Mechanics, vol. 897. Cambridge University Press, 2020.","short":"C.S. Paranjape, Y. Duguet, B. Hof, Journal of Fluid Mechanics 897 (2020).","mla":"Paranjape, Chaitanya S., et al. “Oblique Stripe Solutions of Channel Flow.” Journal of Fluid Mechanics, vol. 897, A7, Cambridge University Press, 2020, doi:10.1017/jfm.2020.322.","ista":"Paranjape CS, Duguet Y, Hof B. 2020. Oblique stripe solutions of channel flow. Journal of Fluid Mechanics. 897, A7.","chicago":"Paranjape, Chaitanya S, Yohann Duguet, and Björn Hof. “Oblique Stripe Solutions of Channel Flow.” Journal of Fluid Mechanics. Cambridge University Press, 2020. https://doi.org/10.1017/jfm.2020.322."},"title":"Oblique stripe solutions of channel flow","author":[{"first_name":"Chaitanya S","id":"3D85B7C4-F248-11E8-B48F-1D18A9856A87","full_name":"Paranjape, Chaitanya S","last_name":"Paranjape"},{"first_name":"Yohann","full_name":"Duguet, Yohann","last_name":"Duguet"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof"}],"external_id":{"isi":["000539132300001"]},"article_processing_charge":"Yes (via OA deal)","acknowledgement":"The authors thank S. Zammert and B. Budanur for useful discussions. J. F. Gibson is gratefully acknowledged for the development and the maintenance of the code Channelflow. Y.D. would like to thank P. Schlatter and D. S. Henningson for an early collaboration on a similar topic in the case of plane Couette flow during the years 2008–2013.","publisher":"Cambridge University Press","quality_controlled":"1","oa":1,"day":"25","publication":"Journal of Fluid Mechanics","has_accepted_license":"1","isi":1,"year":"2020","date_published":"2020-08-25T00:00:00Z","doi":"10.1017/jfm.2020.322","date_created":"2020-06-29T07:59:35Z"},{"publication_status":"published","publication_identifier":{"eissn":["1079-7114"],"issn":["0031-9007"]},"language":[{"iso":"eng"}],"ec_funded":1,"issue":"6","volume":125,"abstract":[{"text":"In laboratory studies and numerical simulations, we observe clear signatures of unstable time-periodic solutions in a moderately turbulent quasi-two-dimensional flow. We validate the dynamical relevance of such solutions by demonstrating that turbulent flows in both experiment and numerics transiently display time-periodic dynamics when they shadow unstable periodic orbits (UPOs). We show that UPOs we computed are also statistically significant, with turbulent flows spending a sizable fraction of the total time near these solutions. As a result, the average rates of energy input and dissipation for the turbulent flow and frequently visited UPOs differ only by a few percent.","lang":"eng"}],"oa_version":"Preprint","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/2008.02367"}],"intvolume":" 125","month":"08","date_updated":"2023-09-05T12:08:29Z","department":[{"_id":"BjHo"}],"_id":"8634","article_type":"original","type":"journal_article","keyword":["General Physics and Astronomy"],"status":"public","year":"2020","isi":1,"publication":"Physical Review Letters","day":"05","date_created":"2020-10-08T17:27:32Z","doi":"10.1103/physrevlett.125.064501","date_published":"2020-08-05T00:00:00Z","acknowledgement":"M. F. S. and R. O. G. acknowledge funding from the National Science Foundation (CMMI-1234436, DMS1125302, CMMI-1725587) and Defense Advanced Research Projects Agency (HR0011-16-2-0033). B. S.has received funding from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007–2013/ under REA Grant Agreement No. 291734.","oa":1,"quality_controlled":"1","publisher":"American Physical Society","citation":{"chicago":"Suri, Balachandra, Logan Kageorge, Roman O. Grigoriev, and Michael F. Schatz. “Capturing Turbulent Dynamics and Statistics in Experiments with Unstable Periodic Orbits.” Physical Review Letters. American Physical Society, 2020. https://doi.org/10.1103/physrevlett.125.064501.","ista":"Suri B, Kageorge L, Grigoriev RO, Schatz MF. 2020. Capturing turbulent dynamics and statistics in experiments with unstable periodic orbits. Physical Review Letters. 125(6), 064501.","mla":"Suri, Balachandra, et al. “Capturing Turbulent Dynamics and Statistics in Experiments with Unstable Periodic Orbits.” Physical Review Letters, vol. 125, no. 6, 064501, American Physical Society, 2020, doi:10.1103/physrevlett.125.064501.","ama":"Suri B, Kageorge L, Grigoriev RO, Schatz MF. Capturing turbulent dynamics and statistics in experiments with unstable periodic orbits. Physical Review Letters. 2020;125(6). doi:10.1103/physrevlett.125.064501","apa":"Suri, B., Kageorge, L., Grigoriev, R. O., & Schatz, M. F. (2020). Capturing turbulent dynamics and statistics in experiments with unstable periodic orbits. Physical Review Letters. American Physical Society. https://doi.org/10.1103/physrevlett.125.064501","ieee":"B. Suri, L. Kageorge, R. O. Grigoriev, and M. F. Schatz, “Capturing turbulent dynamics and statistics in experiments with unstable periodic orbits,” Physical Review Letters, vol. 125, no. 6. American Physical Society, 2020.","short":"B. Suri, L. Kageorge, R.O. Grigoriev, M.F. Schatz, Physical Review Letters 125 (2020)."},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","article_processing_charge":"No","external_id":{"isi":["000555785600005"],"arxiv":["2008.02367"]},"author":[{"first_name":"Balachandra","id":"47A5E706-F248-11E8-B48F-1D18A9856A87","last_name":"Suri","full_name":"Suri, Balachandra"},{"full_name":"Kageorge, Logan","last_name":"Kageorge","first_name":"Logan"},{"full_name":"Grigoriev, Roman O.","last_name":"Grigoriev","first_name":"Roman O."},{"first_name":"Michael F.","last_name":"Schatz","full_name":"Schatz, Michael F."}],"title":"Capturing turbulent dynamics and statistics in experiments with unstable periodic orbits","article_number":"064501","project":[{"name":"International IST Postdoc Fellowship Programme","grant_number":"291734","call_identifier":"FP7","_id":"25681D80-B435-11E9-9278-68D0E5697425"}]},{"issue":"21","volume":117,"related_material":{"link":[{"description":"News on IST Homepage","url":"https://ist.ac.at/en/news/blood-flows-more-turbulent-than-previously-expected/","relation":"press_release"}],"record":[{"relation":"dissertation_contains","id":"12726","status":"public"},{"relation":"dissertation_contains","id":"14530","status":"public"}]},"ec_funded":1,"language":[{"iso":"eng"}],"publication_identifier":{"issn":["00278424"],"eissn":["10916490"]},"publication_status":"published","month":"05","intvolume":" 117","scopus_import":"1","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/2005.11190"}],"oa_version":"Preprint","abstract":[{"lang":"eng","text":"Pulsating flows through tubular geometries are laminar provided that velocities are moderate. This in particular is also believed to apply to cardiovascular flows where inertial forces are typically too low to sustain turbulence. On the other hand, flow instabilities and fluctuating shear stresses are held responsible for a variety of cardiovascular diseases. Here we report a nonlinear instability mechanism for pulsating pipe flow that gives rise to bursts of turbulence at low flow rates. Geometrical distortions of small, yet finite, amplitude are found to excite a state consisting of helical vortices during flow deceleration. The resulting flow pattern grows rapidly in magnitude, breaks down into turbulence, and eventually returns to laminar when the flow accelerates. This scenario causes shear stress fluctuations and flow reversal during each pulsation cycle. Such unsteady conditions can adversely affect blood vessels and have been shown to promote inflammation and dysfunction of the shear stress-sensitive endothelial cell layer."}],"department":[{"_id":"BjHo"}],"date_updated":"2023-11-30T10:55:13Z","status":"public","article_type":"original","type":"journal_article","_id":"7932","doi":"10.1073/pnas.1913716117","date_published":"2020-05-26T00:00:00Z","date_created":"2020-06-07T22:00:51Z","page":"11233-11239","day":"26","publication":"Proceedings of the National Academy of Sciences of the United States of America","isi":1,"year":"2020","quality_controlled":"1","publisher":"National Academy of Sciences","oa":1,"title":"Nonlinear hydrodynamic instability and turbulence in pulsatile flow","author":[{"last_name":"Xu","full_name":"Xu, Duo","id":"3454D55E-F248-11E8-B48F-1D18A9856A87","first_name":"Duo"},{"id":"2A2006B2-F248-11E8-B48F-1D18A9856A87","first_name":"Atul","last_name":"Varshney","full_name":"Varshney, Atul","orcid":"0000-0002-3072-5999"},{"first_name":"Xingyu","id":"34BADBA6-F248-11E8-B48F-1D18A9856A87","last_name":"Ma","orcid":"0000-0002-0179-9737","full_name":"Ma, Xingyu"},{"first_name":"Baofang","full_name":"Song, Baofang","last_name":"Song"},{"last_name":"Riedl","orcid":"0000-0003-4844-6311","full_name":"Riedl, Michael","first_name":"Michael","id":"3BE60946-F248-11E8-B48F-1D18A9856A87"},{"full_name":"Avila, Marc","last_name":"Avila","first_name":"Marc"},{"full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof","id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn"}],"article_processing_charge":"No","external_id":{"isi":["000536797100014"],"arxiv":["2005.11190"]},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"ista":"Xu D, Varshney A, Ma X, Song B, Riedl M, Avila M, Hof B. 2020. Nonlinear hydrodynamic instability and turbulence in pulsatile flow. Proceedings of the National Academy of Sciences of the United States of America. 117(21), 11233–11239.","chicago":"Xu, Duo, Atul Varshney, Xingyu Ma, Baofang Song, Michael Riedl, Marc Avila, and Björn Hof. “Nonlinear Hydrodynamic Instability and Turbulence in Pulsatile Flow.” Proceedings of the National Academy of Sciences of the United States of America. National Academy of Sciences, 2020. https://doi.org/10.1073/pnas.1913716117.","ieee":"D. Xu et al., “Nonlinear hydrodynamic instability and turbulence in pulsatile flow,” Proceedings of the National Academy of Sciences of the United States of America, vol. 117, no. 21. National Academy of Sciences, pp. 11233–11239, 2020.","short":"D. Xu, A. Varshney, X. Ma, B. Song, M. Riedl, M. Avila, B. Hof, Proceedings of the National Academy of Sciences of the United States of America 117 (2020) 11233–11239.","ama":"Xu D, Varshney A, Ma X, et al. Nonlinear hydrodynamic instability and turbulence in pulsatile flow. Proceedings of the National Academy of Sciences of the United States of America. 2020;117(21):11233-11239. doi:10.1073/pnas.1913716117","apa":"Xu, D., Varshney, A., Ma, X., Song, B., Riedl, M., Avila, M., & Hof, B. (2020). Nonlinear hydrodynamic instability and turbulence in pulsatile flow. Proceedings of the National Academy of Sciences of the United States of America. National Academy of Sciences. https://doi.org/10.1073/pnas.1913716117","mla":"Xu, Duo, et al. “Nonlinear Hydrodynamic Instability and Turbulence in Pulsatile Flow.” Proceedings of the National Academy of Sciences of the United States of America, vol. 117, no. 21, National Academy of Sciences, 2020, pp. 11233–39, doi:10.1073/pnas.1913716117."},"project":[{"call_identifier":"FWF","_id":"238B8092-32DE-11EA-91FC-C7463DDC885E","grant_number":"I04188","name":"Instabilities in pulsating pipe flow of Newtonian and complex fluids"},{"grant_number":"754411","name":"ISTplus - Postdoctoral Fellowships","_id":"260C2330-B435-11E9-9278-68D0E5697425","call_identifier":"H2020"}]},{"_id":"7258","status":"public","type":"dissertation","ddc":["532"],"date_updated":"2023-09-15T12:20:08Z","supervisor":[{"last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87"}],"department":[{"_id":"BjHo"}],"file_date_updated":"2021-01-13T23:30:05Z","oa_version":"None","abstract":[{"lang":"eng","text":"Many flows encountered in nature and applications are characterized by a chaotic motion known as turbulence. Turbulent flows generate intense friction with pipe walls and are responsible for considerable amounts of energy losses at world scale. The nature of turbulent friction and techniques aimed at reducing it have been subject of extensive research over the last century, but no definite answer has been found yet. In this thesis we show that in pipes at moderate turbulent Reynolds numbers friction is better described by the power law first introduced by Blasius and not by the Prandtl–von Kármán formula. At higher Reynolds numbers, large scale motions gradually become more important in the flow and can be related to the change in scaling of friction. Next, we present a series of new techniques that can relaminarize turbulence by suppressing a key mechanism that regenerates it at walls, the lift–up effect. In addition, we investigate the process of turbulence decay in several experiments and discuss the drag reduction potential. Finally, we examine the behavior of friction under pulsating conditions inspired by the human heart cycle and we show that under such circumstances turbulent friction can be reduced to produce energy savings."}],"month":"01","alternative_title":["ISTA Thesis"],"language":[{"iso":"eng"}],"file":[{"date_updated":"2021-01-13T23:30:05Z","file_size":26640830,"creator":"dscarsel","date_created":"2020-01-12T15:57:14Z","file_name":"2020_Scarselli_Thesis.zip","content_type":"application/zip","embargo_to":"open_access","access_level":"closed","relation":"source_file","checksum":"4df1ab24e9896635106adde5a54615bf","file_id":"7259"},{"file_size":8515844,"date_updated":"2021-01-13T23:30:05Z","creator":"dscarsel","file_name":"2020_Scarselli_Thesis.pdf","date_created":"2020-01-12T15:56:14Z","content_type":"application/pdf","relation":"main_file","access_level":"open_access","embargo":"2021-01-12","checksum":"48659ab98e3414293c7a721385c2fd1c","file_id":"7260"}],"publication_status":"published","degree_awarded":"PhD","publication_identifier":{"issn":["2663-337X"]},"ec_funded":1,"related_material":{"record":[{"relation":"part_of_dissertation","id":"6228","status":"public"},{"status":"public","id":"6486","relation":"part_of_dissertation"},{"relation":"part_of_dissertation","status":"public","id":"461"},{"status":"public","id":"422","relation":"part_of_dissertation"}]},"project":[{"call_identifier":"FP7","_id":"25152F3A-B435-11E9-9278-68D0E5697425","name":"Decoding the complexity of turbulence at its origin","grant_number":"306589"},{"name":"Eliminating turbulence in oil pipelines","grant_number":"737549","_id":"25104D44-B435-11E9-9278-68D0E5697425","call_identifier":"H2020"},{"_id":"25136C54-B435-11E9-9278-68D0E5697425","name":"Experimental studies of the turbulence transition and transport processes in turbulent Taylor-Couette currents","grant_number":"HO 4393/1-2"}],"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"chicago":"Scarselli, Davide. “New Approaches to Reduce Friction in Turbulent Pipe Flow.” Institute of Science and Technology Austria, 2020. https://doi.org/10.15479/AT:ISTA:7258.","ista":"Scarselli D. 2020. New approaches to reduce friction in turbulent pipe flow. Institute of Science and Technology Austria.","mla":"Scarselli, Davide. New Approaches to Reduce Friction in Turbulent Pipe Flow. Institute of Science and Technology Austria, 2020, doi:10.15479/AT:ISTA:7258.","ieee":"D. Scarselli, “New approaches to reduce friction in turbulent pipe flow,” Institute of Science and Technology Austria, 2020.","short":"D. Scarselli, New Approaches to Reduce Friction in Turbulent Pipe Flow, Institute of Science and Technology Austria, 2020.","apa":"Scarselli, D. (2020). New approaches to reduce friction in turbulent pipe flow. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:7258","ama":"Scarselli D. New approaches to reduce friction in turbulent pipe flow. 2020. doi:10.15479/AT:ISTA:7258"},"title":"New approaches to reduce friction in turbulent pipe flow","article_processing_charge":"No","author":[{"id":"40315C30-F248-11E8-B48F-1D18A9856A87","first_name":"Davide","full_name":"Scarselli, Davide","orcid":"0000-0001-5227-4271","last_name":"Scarselli"}],"oa":1,"publisher":"Institute of Science and Technology Austria","day":"13","year":"2020","has_accepted_license":"1","date_created":"2020-01-12T16:07:26Z","date_published":"2020-01-13T00:00:00Z","doi":"10.15479/AT:ISTA:7258","page":"174"},{"month":"09","alternative_title":["ISTA Thesis"],"oa_version":"None","abstract":[{"text":"Cytoplasm is a gel-like crowded environment composed of tens of thousands of macromolecules, organelles, cytoskeletal networks and cytosol. The structure of the cytoplasm is thought to be highly organized and heterogeneous due to the crowding of its constituents and their effective compartmentalization. In such an environment, the diffusive dynamics of the molecules is very restricted, an effect that is further amplified by clustering and anchoring of molecules. Despite the jammed nature of the cytoplasm at the microscopic scale, large-scale reorganization of cytoplasm is essential for important cellular functions, such as nuclear positioning and cell division. How such mesoscale reorganization of the cytoplasm is achieved, especially for very large cells such as oocytes or syncytial tissues that can span hundreds of micrometers in size, has only begun to be understood.\r\nIn this thesis, I focus on the recent advances in elucidating the molecular, cellular and biophysical principles underlying cytoplasmic organization across different scales, structures and species. First, I outline which of these principles have been identified by reductionist approaches, such as in vitro reconstitution assays, where boundary conditions and components can be modulated at ease. I then describe how the theoretical and experimental framework established in these reduced systems have been applied to their more complex in vivo counterparts, in particular oocytes and embryonic syncytial structures, and discuss how such complex biological systems can initiate symmetry breaking and establish patterning.\r\nSpecifically, I examine an example of large-scale reorganizations taking place in zebrafish embryos, where extensive cytoplasmic streaming leads to the segregation of cytoplasm from yolk granules along the animal-vegetal axis of the embryo. Using biophysical experimentation and theory, I investigate the forces underlying this process, to show that this process does not rely on cortical actin reorganization, as previously thought, but instead on a cell-cycle-dependent bulk actin polymerization wave traveling from the animal to the vegetal pole of the embryo. This wave functions in segregation by both pulling cytoplasm animally and pushing yolk granules vegetally. Cytoplasm pulling is mediated by bulk actin network flows exerting friction forces on the cytoplasm, while yolk granule pushing is achieved by a mechanism closely resembling actin comet formation on yolk granules. This study defines a novel role of bulk actin polymerization waves in embryo polarization via cytoplasmic segregation. Lastly, I describe the cytoplasmic reorganizations taking place during zebrafish oocyte maturation, where the initial segregation of the cytoplasm and yolk granules occurs. Here, I demonstrate a previously uncharacterized wave of microtubule aster formation, traveling the oocyte along the animal-vegetal axis. Further research is required to determine the role of such microtubule structures in cytoplasmic reorganizations therein.\r\nCollectively, these studies provide further evidence for the coupling between cell cytoskeleton and cell cycle machinery, which can underlie a core self-organizing mechanism for orchestrating large-scale reorganizations in a cell-cycle-tunable manner, where the modulations of the force-generating machinery and cytoplasmic mechanics can be harbored to fulfill cellular functions.","lang":"eng"}],"acknowledged_ssus":[{"_id":"PreCl"},{"_id":"Bio"},{"_id":"EM-Fac"}],"related_material":{"record":[{"id":"661","status":"public","relation":"part_of_dissertation"},{"relation":"part_of_dissertation","id":"6508","status":"public"},{"relation":"part_of_dissertation","id":"7001","status":"public"},{"status":"public","id":"735","relation":"part_of_dissertation"}]},"file":[{"content_type":"application/vnd.openxmlformats-officedocument.wordprocessingml.document","embargo_to":"open_access","access_level":"closed","relation":"source_file","checksum":"6e47871c74f85008b9876112eb3fcfa1","file_id":"8351","date_updated":"2021-09-11T22:30:05Z","file_size":65194814,"creator":"sshamip","date_created":"2020-09-09T11:06:27Z","file_name":"Shayan-Thesis-Final.docx"},{"embargo":"2021-09-10","file_id":"8352","checksum":"1b44c57f04d7e8a6fe41b1c9c55a52a3","content_type":"application/pdf","relation":"main_file","access_level":"open_access","file_name":"Shayan-Thesis-Final.pdf","date_created":"2020-09-09T11:06:13Z","file_size":23729605,"date_updated":"2021-09-11T22:30:05Z","creator":"sshamip"}],"language":[{"iso":"eng"}],"publication_identifier":{"issn":["2663-337X"]},"publication_status":"published","degree_awarded":"PhD","status":"public","type":"dissertation","_id":"8350","department":[{"_id":"BjHo"},{"_id":"CaHe"}],"file_date_updated":"2021-09-11T22:30:05Z","ddc":["570"],"supervisor":[{"first_name":"Carl-Philipp J","id":"39427864-F248-11E8-B48F-1D18A9856A87","full_name":"Heisenberg, Carl-Philipp J","orcid":"0000-0002-0912-4566","last_name":"Heisenberg"},{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof"}],"date_updated":"2023-09-27T14:16:45Z","publisher":"Institute of Science and Technology Austria","oa":1,"acknowledgement":"I would have had no fish and hence no results without our wonderful fish facility crew, Verena Mayer, Eva Schlegl, Andreas Mlak and Matthias Nowak. Special thanks to Verena for being always happy to help and dealing with our chaotic schedules in the lab. Danke auch, Verena, für deine Geduld, mit mir auf Deutsch zu sprechen. Das hat mir sehr geholfen.\r\nSpecial thanks to the Bioimaging and EM facilities at IST Austria for supporting us every day. Very special thanks would go to Robert Hauschild for his continuous support on data analysis and also to Jack Merrin for designing and building microfabricated chambers for the project and for the various discussions on making zebrafish extracts.","doi":"10.15479/AT:ISTA:8350","date_published":"2020-09-09T00:00:00Z","date_created":"2020-09-09T11:12:10Z","page":"107","day":"09","has_accepted_license":"1","year":"2020","title":"Bulk actin dynamics drive phase segregation in zebrafish oocytes ","author":[{"first_name":"Shayan","id":"40B34FE2-F248-11E8-B48F-1D18A9856A87","full_name":"Shamipour, Shayan","last_name":"Shamipour"}],"article_processing_charge":"No","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"ista":"Shamipour S. 2020. Bulk actin dynamics drive phase segregation in zebrafish oocytes . Institute of Science and Technology Austria.","chicago":"Shamipour, Shayan. “Bulk Actin Dynamics Drive Phase Segregation in Zebrafish Oocytes .” Institute of Science and Technology Austria, 2020. https://doi.org/10.15479/AT:ISTA:8350.","apa":"Shamipour, S. (2020). Bulk actin dynamics drive phase segregation in zebrafish oocytes . Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:8350","ama":"Shamipour S. Bulk actin dynamics drive phase segregation in zebrafish oocytes . 2020. doi:10.15479/AT:ISTA:8350","ieee":"S. Shamipour, “Bulk actin dynamics drive phase segregation in zebrafish oocytes ,” Institute of Science and Technology Austria, 2020.","short":"S. Shamipour, Bulk Actin Dynamics Drive Phase Segregation in Zebrafish Oocytes , Institute of Science and Technology Austria, 2020.","mla":"Shamipour, Shayan. Bulk Actin Dynamics Drive Phase Segregation in Zebrafish Oocytes . Institute of Science and Technology Austria, 2020, doi:10.15479/AT:ISTA:8350."}},{"volume":863,"ec_funded":1,"publication_status":"published","language":[{"iso":"eng"}],"scopus_import":"1","main_file_link":[{"url":"https://arxiv.org/abs/1902.07931","open_access":"1"}],"month":"03","intvolume":" 863","abstract":[{"lang":"eng","text":"The hairpin instability of a jet in a crossflow (JICF) for a low jet-to-crossflow velocity ratio is investigated experimentally for a velocity ratio range of R ∈ (0.14, 0.75) and crossflow Reynolds numbers ReD ∈ (260, 640). From spectral analysis we characterize the Strouhal number and amplitude of the hairpin instability as a function of R and ReD. We demonstrate that the dynamics of the hairpins is well described by the Landau model, and, hence, that the instability occurs through Hopf bifurcation, similarly to other hydrodynamical oscillators such as wake behind different bluff bodies. Using the Landau model, we determine the precise threshold values of hairpin shedding. We also study the spatial dependence of this hydrodynamical instability, which shows a global behaviour."}],"oa_version":"Preprint","department":[{"_id":"BjHo"}],"date_updated":"2023-08-24T14:43:13Z","article_type":"original","type":"journal_article","status":"public","_id":"5943","page":"386-406","doi":"10.1017/jfm.2018.974","date_published":"2019-03-25T00:00:00Z","date_created":"2019-02-10T22:59:15Z","isi":1,"year":"2019","day":"25","publication":"Journal of Fluid Mechanics","publisher":"Cambridge University Press","quality_controlled":"1","oa":1,"author":[{"first_name":"Lukasz","id":"2C9AF1C2-F248-11E8-B48F-1D18A9856A87","last_name":"Klotz","full_name":"Klotz, Lukasz","orcid":"0000-0003-1740-7635"},{"first_name":"Konrad","full_name":"Gumowski, Konrad","last_name":"Gumowski"},{"last_name":"Wesfreid","full_name":"Wesfreid, José Eduardo","first_name":"José Eduardo"}],"external_id":{"arxiv":["1902.07931"],"isi":["000526029100016"]},"article_processing_charge":"No","title":"Experiments on a jet in a crossflow in the low-velocity-ratio regime","citation":{"ieee":"L. Klotz, K. Gumowski, and J. E. Wesfreid, “Experiments on a jet in a crossflow in the low-velocity-ratio regime,” Journal of Fluid Mechanics, vol. 863. Cambridge University Press, pp. 386–406, 2019.","short":"L. Klotz, K. Gumowski, J.E. Wesfreid, Journal of Fluid Mechanics 863 (2019) 386–406.","ama":"Klotz L, Gumowski K, Wesfreid JE. Experiments on a jet in a crossflow in the low-velocity-ratio regime. Journal of Fluid Mechanics. 2019;863:386-406. doi:10.1017/jfm.2018.974","apa":"Klotz, L., Gumowski, K., & Wesfreid, J. E. (2019). Experiments on a jet in a crossflow in the low-velocity-ratio regime. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2018.974","mla":"Klotz, Lukasz, et al. “Experiments on a Jet in a Crossflow in the Low-Velocity-Ratio Regime.” Journal of Fluid Mechanics, vol. 863, Cambridge University Press, 2019, pp. 386–406, doi:10.1017/jfm.2018.974.","ista":"Klotz L, Gumowski K, Wesfreid JE. 2019. Experiments on a jet in a crossflow in the low-velocity-ratio regime. Journal of Fluid Mechanics. 863, 386–406.","chicago":"Klotz, Lukasz, Konrad Gumowski, and José Eduardo Wesfreid. “Experiments on a Jet in a Crossflow in the Low-Velocity-Ratio Regime.” Journal of Fluid Mechanics. Cambridge University Press, 2019. https://doi.org/10.1017/jfm.2018.974."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","project":[{"grant_number":"754411","name":"ISTplus - Postdoctoral Fellowships","_id":"260C2330-B435-11E9-9278-68D0E5697425","call_identifier":"H2020"}]},{"article_number":"013122","title":"State space geometry of the chaotic pilot-wave hydrodynamics","external_id":{"arxiv":["1812.09011"],"isi":["000457409100028"]},"article_processing_charge":"No","author":[{"full_name":"Budanur, Nazmi B","orcid":"0000-0003-0423-5010","last_name":"Budanur","id":"3EA1010E-F248-11E8-B48F-1D18A9856A87","first_name":"Nazmi B"},{"full_name":"Fleury, Marc","last_name":"Fleury","first_name":"Marc"}],"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"chicago":"Budanur, Nazmi B, and Marc Fleury. “State Space Geometry of the Chaotic Pilot-Wave Hydrodynamics.” Chaos: An Interdisciplinary Journal of Nonlinear Science. AIP Publishing, 2019. https://doi.org/10.1063/1.5058279.","ista":"Budanur NB, Fleury M. 2019. State space geometry of the chaotic pilot-wave hydrodynamics. Chaos: An Interdisciplinary Journal of Nonlinear Science. 29(1), 013122.","mla":"Budanur, Nazmi B., and Marc Fleury. “State Space Geometry of the Chaotic Pilot-Wave Hydrodynamics.” Chaos: An Interdisciplinary Journal of Nonlinear Science, vol. 29, no. 1, 013122, AIP Publishing, 2019, doi:10.1063/1.5058279.","ieee":"N. B. Budanur and M. Fleury, “State space geometry of the chaotic pilot-wave hydrodynamics,” Chaos: An Interdisciplinary Journal of Nonlinear Science, vol. 29, no. 1. AIP Publishing, 2019.","short":"N.B. Budanur, M. Fleury, Chaos: An Interdisciplinary Journal of Nonlinear Science 29 (2019).","ama":"Budanur NB, Fleury M. State space geometry of the chaotic pilot-wave hydrodynamics. Chaos: An Interdisciplinary Journal of Nonlinear Science. 2019;29(1). doi:10.1063/1.5058279","apa":"Budanur, N. B., & Fleury, M. (2019). State space geometry of the chaotic pilot-wave hydrodynamics. Chaos: An Interdisciplinary Journal of Nonlinear Science. AIP Publishing. https://doi.org/10.1063/1.5058279"},"oa":1,"publisher":"AIP Publishing","quality_controlled":"1","date_created":"2019-01-23T08:35:09Z","doi":"10.1063/1.5058279","date_published":"2019-01-22T00:00:00Z","publication":"Chaos: An Interdisciplinary Journal of Nonlinear Science","day":"22","year":"2019","isi":1,"status":"public","type":"journal_article","article_type":"original","_id":"5878","department":[{"_id":"BjHo"}],"date_updated":"2023-08-25T10:16:11Z","intvolume":" 29","month":"01","main_file_link":[{"url":"https://arxiv.org/abs/1812.09011","open_access":"1"}],"scopus_import":"1","oa_version":"Preprint","abstract":[{"lang":"eng","text":"We consider the motion of a droplet bouncing on a vibrating bath of the same fluid in the presence of a central potential. We formulate a rotation symmetry-reduced description of this system, which allows for the straightforward application of dynamical systems theory tools. As an illustration of the utility of the symmetry reduction, we apply it to a model of the pilot-wave system with a central harmonic force. We begin our analysis by identifying local bifurcations and the onset of chaos. We then describe the emergence of chaotic regions and their merging bifurcations, which lead to the formation of a global attractor. In this final regime, the droplet’s angular momentum spontaneously changes its sign as observed in the experiments of Perrard et al."}],"related_material":{"link":[{"relation":"erratum","url":"https://aip.scitation.org/doi/abs/10.1063/1.5097157"}]},"issue":"1","volume":29,"language":[{"iso":"eng"}],"publication_status":"published","publication_identifier":{"eissn":["1089-7682"],"issn":["1054-1500"]}},{"department":[{"_id":"BjHo"}],"date_updated":"2023-08-25T10:19:55Z","status":"public","article_type":"original","type":"journal_article","_id":"6413","volume":117,"language":[{"iso":"eng"}],"publication_status":"published","publication_identifier":{"issn":["03019322"]},"intvolume":" 117","month":"08","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1902.07351"}],"scopus_import":"1","oa_version":"Preprint","abstract":[{"lang":"eng","text":"Phase-field methods have long been used to model the flow of immiscible fluids. Their ability to naturally capture interface topological changes is widely recognized, but their accuracy in simulating flows of real fluids in practical geometries is not established. We here quantitatively investigate the convergence of the phase-field method to the sharp-interface limit with simulations of two-phase pipe flow. We focus on core-annular flows, in which a highly viscous fluid is lubricated by a less viscous fluid, and validate our simulations with an analytic laminar solution, a formal linear stability analysis and also in the fully nonlinear regime. We demonstrate the ability of the phase-field method to accurately deal with non-rectangular geometry, strong advection, unsteady fluctuations and large viscosity contrast. We argue that phase-field methods are very promising for quantitatively studying moderately turbulent flows, especially at high concentrations of the disperse phase."}],"title":"Phase-field simulation of core-annular pipe flow","article_processing_charge":"No","external_id":{"arxiv":["1902.07351"],"isi":["000474496000002"]},"author":[{"first_name":"Baofang","last_name":"Song","full_name":"Song, Baofang"},{"full_name":"Plana, Carlos","last_name":"Plana","first_name":"Carlos"},{"last_name":"Lopez Alonso","full_name":"Lopez Alonso, Jose M","orcid":"0000-0002-0384-2022","id":"40770848-F248-11E8-B48F-1D18A9856A87","first_name":"Jose M"},{"last_name":"Avila","full_name":"Avila, Marc","first_name":"Marc"}],"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"short":"B. Song, C. Plana, J.M. Lopez Alonso, M. Avila, International Journal of Multiphase Flow 117 (2019) 14–24.","ieee":"B. Song, C. Plana, J. M. Lopez Alonso, and M. Avila, “Phase-field simulation of core-annular pipe flow,” International Journal of Multiphase Flow, vol. 117. Elsevier, pp. 14–24, 2019.","apa":"Song, B., Plana, C., Lopez Alonso, J. M., & Avila, M. (2019). Phase-field simulation of core-annular pipe flow. International Journal of Multiphase Flow. Elsevier. https://doi.org/10.1016/j.ijmultiphaseflow.2019.04.027","ama":"Song B, Plana C, Lopez Alonso JM, Avila M. Phase-field simulation of core-annular pipe flow. International Journal of Multiphase Flow. 2019;117:14-24. doi:10.1016/j.ijmultiphaseflow.2019.04.027","mla":"Song, Baofang, et al. “Phase-Field Simulation of Core-Annular Pipe Flow.” International Journal of Multiphase Flow, vol. 117, Elsevier, 2019, pp. 14–24, doi:10.1016/j.ijmultiphaseflow.2019.04.027.","ista":"Song B, Plana C, Lopez Alonso JM, Avila M. 2019. Phase-field simulation of core-annular pipe flow. International Journal of Multiphase Flow. 117, 14–24.","chicago":"Song, Baofang, Carlos Plana, Jose M Lopez Alonso, and Marc Avila. “Phase-Field Simulation of Core-Annular Pipe Flow.” International Journal of Multiphase Flow. Elsevier, 2019. https://doi.org/10.1016/j.ijmultiphaseflow.2019.04.027."},"date_created":"2019-05-13T07:58:35Z","doi":"10.1016/j.ijmultiphaseflow.2019.04.027","date_published":"2019-08-01T00:00:00Z","page":"14-24","publication":"International Journal of Multiphase Flow","day":"01","year":"2019","isi":1,"oa":1,"quality_controlled":"1","publisher":"Elsevier"},{"author":[{"id":"3EA1010E-F248-11E8-B48F-1D18A9856A87","first_name":"Nazmi B","orcid":"0000-0003-0423-5010","full_name":"Budanur, Nazmi B","last_name":"Budanur"},{"first_name":"Akshunna","last_name":"Dogra","full_name":"Dogra, Akshunna"},{"orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof","id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn"}],"external_id":{"arxiv":["1810.02211"],"isi":["000493510400001"]},"article_processing_charge":"No","title":"Geometry of transient chaos in streamwise-localized pipe flow turbulence","citation":{"ama":"Budanur NB, Dogra A, Hof B. Geometry of transient chaos in streamwise-localized pipe flow turbulence. Physical Review Fluids. 2019;4(10):102401. doi:10.1103/PhysRevFluids.4.102401","apa":"Budanur, N. B., Dogra, A., & Hof, B. (2019). Geometry of transient chaos in streamwise-localized pipe flow turbulence. Physical Review Fluids. American Physical Society. https://doi.org/10.1103/PhysRevFluids.4.102401","short":"N.B. Budanur, A. Dogra, B. Hof, Physical Review Fluids 4 (2019) 102401.","ieee":"N. B. Budanur, A. Dogra, and B. Hof, “Geometry of transient chaos in streamwise-localized pipe flow turbulence,” Physical Review Fluids, vol. 4, no. 10. American Physical Society, p. 102401, 2019.","mla":"Budanur, Nazmi B., et al. “Geometry of Transient Chaos in Streamwise-Localized Pipe Flow Turbulence.” Physical Review Fluids, vol. 4, no. 10, American Physical Society, 2019, p. 102401, doi:10.1103/PhysRevFluids.4.102401.","ista":"Budanur NB, Dogra A, Hof B. 2019. Geometry of transient chaos in streamwise-localized pipe flow turbulence. Physical Review Fluids. 4(10), 102401.","chicago":"Budanur, Nazmi B, Akshunna Dogra, and Björn Hof. “Geometry of Transient Chaos in Streamwise-Localized Pipe Flow Turbulence.” Physical Review Fluids. American Physical Society, 2019. https://doi.org/10.1103/PhysRevFluids.4.102401."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","page":"102401","doi":"10.1103/PhysRevFluids.4.102401","date_published":"2019-10-01T00:00:00Z","date_created":"2019-11-04T10:04:01Z","isi":1,"year":"2019","day":"01","publication":"Physical Review Fluids","publisher":"American Physical Society","quality_controlled":"1","oa":1,"department":[{"_id":"BjHo"}],"date_updated":"2023-08-30T07:20:03Z","article_type":"original","type":"journal_article","status":"public","_id":"6978","issue":"10","volume":4,"publication_status":"published","language":[{"iso":"eng"}],"scopus_import":"1","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1810.02211"}],"month":"10","intvolume":" 4","abstract":[{"text":"In pipes and channels, the onset of turbulence is initially dominated by localizedtransients, which lead to sustained turbulence through their collective dynamics. In thepresent work, we study numerically the localized turbulence in pipe flow and elucidate astate space structure that gives rise to transient chaos. Starting from the basin boundaryseparating laminar and turbulent flow, we identify transverse homoclinic orbits, thepresence of which necessitates a homoclinic tangle and chaos. A direct consequence ofthe homoclinic tangle is the fractal nature of the laminar-turbulent boundary, which wasconjectured in various earlier studies. By mapping the transverse intersections between thestable and unstable manifold of a periodic orbit, we identify the gateways that promote anescape from turbulence.","lang":"eng"}],"acknowledged_ssus":[{"_id":"ScienComp"}],"oa_version":"Preprint"},{"oa":1,"publisher":"CUP","quality_controlled":"1","publication":"Journal of Fluid Mechanics","day":"10","year":"2019","isi":1,"date_created":"2020-01-29T16:05:19Z","date_published":"2019-09-10T00:00:00Z","doi":"10.1017/jfm.2019.486","page":"699-719","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"ista":"Lopez Alonso JM, Choueiri GH, Hof B. 2019. Dynamics of viscoelastic pipe flow at low Reynolds numbers in the maximum drag reduction limit. Journal of Fluid Mechanics. 874, 699–719.","chicago":"Lopez Alonso, Jose M, George H Choueiri, and Björn Hof. “Dynamics of Viscoelastic Pipe Flow at Low Reynolds Numbers in the Maximum Drag Reduction Limit.” Journal of Fluid Mechanics. CUP, 2019. https://doi.org/10.1017/jfm.2019.486.","ama":"Lopez Alonso JM, Choueiri GH, Hof B. Dynamics of viscoelastic pipe flow at low Reynolds numbers in the maximum drag reduction limit. Journal of Fluid Mechanics. 2019;874:699-719. doi:10.1017/jfm.2019.486","apa":"Lopez Alonso, J. M., Choueiri, G. H., & Hof, B. (2019). Dynamics of viscoelastic pipe flow at low Reynolds numbers in the maximum drag reduction limit. Journal of Fluid Mechanics. CUP. https://doi.org/10.1017/jfm.2019.486","ieee":"J. M. Lopez Alonso, G. H. Choueiri, and B. Hof, “Dynamics of viscoelastic pipe flow at low Reynolds numbers in the maximum drag reduction limit,” Journal of Fluid Mechanics, vol. 874. CUP, pp. 699–719, 2019.","short":"J.M. Lopez Alonso, G.H. Choueiri, B. Hof, Journal of Fluid Mechanics 874 (2019) 699–719.","mla":"Lopez Alonso, Jose M., et al. “Dynamics of Viscoelastic Pipe Flow at Low Reynolds Numbers in the Maximum Drag Reduction Limit.” Journal of Fluid Mechanics, vol. 874, CUP, 2019, pp. 699–719, doi:10.1017/jfm.2019.486."},"title":"Dynamics of viscoelastic pipe flow at low Reynolds numbers in the maximum drag reduction limit","external_id":{"arxiv":["1808.04080"],"isi":["000475349900001"]},"article_processing_charge":"No","author":[{"last_name":"Lopez Alonso","orcid":"0000-0002-0384-2022","full_name":"Lopez Alonso, Jose M","id":"40770848-F248-11E8-B48F-1D18A9856A87","first_name":"Jose M"},{"first_name":"George H","id":"448BD5BC-F248-11E8-B48F-1D18A9856A87","last_name":"Choueiri","full_name":"Choueiri, George H"},{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof"}],"oa_version":"Preprint","abstract":[{"text":"Polymer additives can substantially reduce the drag of turbulent flows and the upperlimit, the so called “maximum drag reduction” (MDR) asymptote is universal, i.e. inde-pendent of the type of polymer and solvent used. Until recently, the consensus was that,in this limit, flows are in a marginal state where only a minimal level of turbulence activ-ity persists. Observations in direct numerical simulations using minimal sized channelsappeared to support this view and reported long “hibernation” periods where turbu-lence is marginalized. In simulations of pipe flow we find that, indeed, with increasingWeissenberg number (Wi), turbulence expresses long periods of hibernation if the domainsize is small. However, with increasing pipe length, the temporal hibernation continuouslyalters to spatio-temporal intermittency and here the flow consists of turbulent puffs sur-rounded by laminar flow. Moreover, upon an increase in Wi, the flow fully relaminarises,in agreement with recent experiments. At even larger Wi, a different instability is en-countered causing a drag increase towards MDR. Our findings hence link earlier minimalflow unit simulations with recent experiments and confirm that the addition of polymersinitially suppresses Newtonian turbulence and leads to a reverse transition. The MDRstate on the other hand results from a separate instability and the underlying dynamicscorresponds to the recently proposed state of elasto-inertial-turbulence (EIT).","lang":"eng"}],"intvolume":" 874","month":"09","main_file_link":[{"url":"https://arxiv.org/abs/1808.04080","open_access":"1"}],"scopus_import":"1","language":[{"iso":"eng"}],"publication_status":"published","publication_identifier":{"eissn":["1469-7645"],"issn":["0022-1120"]},"volume":874,"_id":"7397","status":"public","article_type":"original","type":"journal_article","date_updated":"2023-09-06T15:36:36Z","department":[{"_id":"BjHo"}]},{"_id":"6957","keyword":["Instabilities","Turbulence","Nonlinear dynamics"],"status":"public","type":"dissertation","ddc":["532"],"date_updated":"2023-09-07T12:53:25Z","supervisor":[{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754"}],"department":[{"_id":"BjHo"}],"file_date_updated":"2020-07-14T12:47:46Z","oa_version":"Published Version","abstract":[{"text":"In many shear flows like pipe flow, plane Couette flow, plane Poiseuille flow, etc. turbulence emerges subcritically. Here, when subjected to strong enough perturbations, the flow becomes turbulent in spite of the laminar base flow being linearly stable. The nature of this instability has puzzled the scientific community for decades. At onset, turbulence appears in localized patches and flows are spatio-temporally intermittent. In pipe flow the localized turbulent structures are referred to as puffs and in planar flows like plane Couette and channel flow, patches arise in the form of localized oblique bands. In this thesis, we study the onset of turbulence in channel flow in direct numerical simulations from a dynamical system theory perspective, as well as by performing experiments in a large aspect ratio channel.\r\n\r\nThe aim of the experimental work is to determine the critical Reynolds number where turbulence first becomes sustained. Recently, the onset of turbulence has been described in analogy to absorbing state phase transition (i.e. directed percolation). In particular, it has been shown that the critical point can be estimated from the competition between spreading and decay processes. Here, by performing experiments, we identify the mechanisms underlying turbulence proliferation in channel flow and find the critical Reynolds number, above which turbulence becomes sustained. Above the critical point, the continuous growth at the tip of the stripes outweighs the stochastic shedding of turbulent patches at the tail and the stripes expand. For growing stripes, the probability to decay decreases while the probability of stripe splitting increases. Consequently, and unlike for the puffs in pipe flow, neither of these two processes is time-independent i.e. memoryless. Coupling between stripe expansion and creation of new stripes via splitting leads to a significantly lower critical point ($Re_c=670+/-10$) than most earlier studies suggest. \r\n\r\nWhile the above approach sheds light on how turbulence first becomes sustained, it provides no insight into the origin of the stripes themselves. In the numerical part of the thesis we investigate how turbulent stripes form from invariant solutions of the Navier-Stokes equations. The origin of these turbulent stripes can be identified by applying concepts from the dynamical system theory. In doing so, we identify the exact coherent structures underlying stripes and their bifurcations and how they give rise to the turbulent attractor in phase space. We first report a family of localized nonlinear traveling wave solutions of the Navier-Stokes equations in channel flow. These solutions show structural similarities with turbulent stripes in experiments like obliqueness, quasi-streamwise streaks and vortices, etc. A parametric study of these traveling wave solution is performed, with parameters like Reynolds number, stripe tilt angle and domain size, including the stability of the solutions. These solutions emerge through saddle-node bifurcations and form a phase space skeleton for the turbulent stripes observed in the experiments. The lower branches of these TW solutions at different tilt angles undergo Hopf bifurcation and new solutions branches of relative periodic orbits emerge. These RPO solutions do not belong to the same family and therefore the routes to chaos for different angles are different. \r\n\r\nIn shear flows, turbulence at onset is transient in nature. Consequently,turbulence can not be tracked to lower Reynolds numbers, where the dynamics may simplify. Before this happens, turbulence becomes short-lived and laminarizes. In the last part of the thesis, we show that using numerical simulations we can continue turbulent stripes in channel flow past the 'relaminarization barrier' all the way to their origin. Here, turbulent stripe dynamics simplifies and the fluctuations are no longer stochastic and the stripe settles down to a relative periodic orbit. This relative periodic orbit originates from the aforementioned traveling wave solutions. Starting from the relative periodic orbit, a small increase in speed i.e. Reynolds number gives rise to chaos and the attractor dimension sharply increases in contrast to the classical transition scenario where the instabilities affect the flow globally and give rise to much more gradual route to turbulence.","lang":"eng"}],"month":"10","alternative_title":["ISTA Thesis"],"language":[{"iso":"eng"}],"file":[{"file_name":"Chaitanya_Paranjape_source_files_tex_figures.zip","date_created":"2019-10-23T09:54:43Z","file_size":45828099,"date_updated":"2020-07-14T12:47:46Z","creator":"cparanjape","file_id":"6962","checksum":"7ba298ba0ce7e1d11691af6b8eaf0a0a","content_type":"application/zip","relation":"source_file","access_level":"closed"},{"creator":"cparanjape","date_updated":"2020-07-14T12:47:46Z","file_size":19504197,"date_created":"2019-10-23T10:37:09Z","file_name":"Chaitanya_Paranjape_Thesis.pdf","access_level":"open_access","relation":"main_file","content_type":"application/pdf","checksum":"642697618314e31ac31392da7909c2d9","file_id":"6963"}],"publication_status":"published","degree_awarded":"PhD","publication_identifier":{"eissn":["2663-337X"]},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"mla":"Paranjape, Chaitanya S. Onset of Turbulence in Plane Poiseuille Flow. Institute of Science and Technology Austria, 2019, doi:10.15479/AT:ISTA:6957.","apa":"Paranjape, C. S. (2019). Onset of turbulence in plane Poiseuille flow. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:6957","ama":"Paranjape CS. Onset of turbulence in plane Poiseuille flow. 2019. doi:10.15479/AT:ISTA:6957","short":"C.S. Paranjape, Onset of Turbulence in Plane Poiseuille Flow, Institute of Science and Technology Austria, 2019.","ieee":"C. S. Paranjape, “Onset of turbulence in plane Poiseuille flow,” Institute of Science and Technology Austria, 2019.","chicago":"Paranjape, Chaitanya S. “Onset of Turbulence in Plane Poiseuille Flow.” Institute of Science and Technology Austria, 2019. https://doi.org/10.15479/AT:ISTA:6957.","ista":"Paranjape CS. 2019. Onset of turbulence in plane Poiseuille flow. Institute of Science and Technology Austria."},"title":"Onset of turbulence in plane Poiseuille flow","article_processing_charge":"No","author":[{"full_name":"Paranjape, Chaitanya S","last_name":"Paranjape","first_name":"Chaitanya S","id":"3D85B7C4-F248-11E8-B48F-1D18A9856A87"}],"oa":1,"publisher":"Institute of Science and Technology Austria","day":"24","year":"2019","has_accepted_license":"1","date_created":"2019-10-22T12:08:43Z","doi":"10.15479/AT:ISTA:6957","date_published":"2019-10-24T00:00:00Z","page":"138"},{"project":[{"grant_number":"679239","name":"Self-Organization of the Bacterial Cell","_id":"2595697A-B435-11E9-9278-68D0E5697425","call_identifier":"H2020"},{"name":"Reconstitution of Bacterial Cell Division Using Purified Components","_id":"260D98C8-B435-11E9-9278-68D0E5697425"}],"article_number":"5744","author":[{"id":"38FCDB4C-F248-11E8-B48F-1D18A9856A87","first_name":"Paulo R","last_name":"Dos Santos Caldas","orcid":"0000-0001-6730-4461","full_name":"Dos Santos Caldas, Paulo R"},{"full_name":"Lopez Pelegrin, Maria D","last_name":"Lopez Pelegrin","first_name":"Maria D","id":"319AA9CE-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Daniel J. G.","last_name":"Pearce","full_name":"Pearce, Daniel J. G."},{"first_name":"Nazmi B","id":"3EA1010E-F248-11E8-B48F-1D18A9856A87","last_name":"Budanur","full_name":"Budanur, Nazmi B","orcid":"0000-0003-0423-5010"},{"last_name":"Brugués","full_name":"Brugués, Jan","first_name":"Jan"},{"first_name":"Martin","id":"462D4284-F248-11E8-B48F-1D18A9856A87","full_name":"Loose, Martin","orcid":"0000-0001-7309-9724","last_name":"Loose"}],"external_id":{"isi":["000503009300001"]},"article_processing_charge":"No","title":"Cooperative ordering of treadmilling filaments in cytoskeletal networks of FtsZ and its crosslinker ZapA","citation":{"ista":"Dos Santos Caldas PR, Lopez Pelegrin MD, Pearce DJG, Budanur NB, Brugués J, Loose M. 2019. Cooperative ordering of treadmilling filaments in cytoskeletal networks of FtsZ and its crosslinker ZapA. Nature Communications. 10, 5744.","chicago":"Dos Santos Caldas, Paulo R, Maria D Lopez Pelegrin, Daniel J. G. Pearce, Nazmi B Budanur, Jan Brugués, and Martin Loose. “Cooperative Ordering of Treadmilling Filaments in Cytoskeletal Networks of FtsZ and Its Crosslinker ZapA.” Nature Communications. Springer Nature, 2019. https://doi.org/10.1038/s41467-019-13702-4.","short":"P.R. Dos Santos Caldas, M.D. Lopez Pelegrin, D.J.G. Pearce, N.B. Budanur, J. Brugués, M. Loose, Nature Communications 10 (2019).","ieee":"P. R. Dos Santos Caldas, M. D. Lopez Pelegrin, D. J. G. Pearce, N. B. Budanur, J. Brugués, and M. Loose, “Cooperative ordering of treadmilling filaments in cytoskeletal networks of FtsZ and its crosslinker ZapA,” Nature Communications, vol. 10. Springer Nature, 2019.","ama":"Dos Santos Caldas PR, Lopez Pelegrin MD, Pearce DJG, Budanur NB, Brugués J, Loose M. Cooperative ordering of treadmilling filaments in cytoskeletal networks of FtsZ and its crosslinker ZapA. Nature Communications. 2019;10. doi:10.1038/s41467-019-13702-4","apa":"Dos Santos Caldas, P. R., Lopez Pelegrin, M. D., Pearce, D. J. G., Budanur, N. B., Brugués, J., & Loose, M. (2019). Cooperative ordering of treadmilling filaments in cytoskeletal networks of FtsZ and its crosslinker ZapA. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-019-13702-4","mla":"Dos Santos Caldas, Paulo R., et al. “Cooperative Ordering of Treadmilling Filaments in Cytoskeletal Networks of FtsZ and Its Crosslinker ZapA.” Nature Communications, vol. 10, 5744, Springer Nature, 2019, doi:10.1038/s41467-019-13702-4."},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","quality_controlled":"1","publisher":"Springer Nature","oa":1,"date_published":"2019-12-17T00:00:00Z","doi":"10.1038/s41467-019-13702-4","date_created":"2019-12-20T12:22:57Z","has_accepted_license":"1","isi":1,"year":"2019","day":"17","publication":"Nature Communications","article_type":"original","type":"journal_article","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"status":"public","_id":"7197","department":[{"_id":"MaLo"},{"_id":"BjHo"}],"file_date_updated":"2020-07-14T12:47:53Z","date_updated":"2023-09-07T13:18:51Z","ddc":["570"],"scopus_import":"1","month":"12","intvolume":" 10","abstract":[{"text":"During bacterial cell division, the tubulin-homolog FtsZ forms a ring-like structure at the center of the cell. This Z-ring not only organizes the division machinery, but treadmilling of FtsZ filaments was also found to play a key role in distributing proteins at the division site. What regulates the architecture, dynamics and stability of the Z-ring is currently unknown, but FtsZ-associated proteins are known to play an important role. Here, using an in vitro reconstitution approach, we studied how the well-conserved protein ZapA affects FtsZ treadmilling and filament organization into large-scale patterns. Using high-resolution fluorescence microscopy and quantitative image analysis, we found that ZapA cooperatively increases the spatial order of the filament network, but binds only transiently to FtsZ filaments and has no effect on filament length and treadmilling velocity. Together, our data provides a model for how FtsZ-associated proteins can increase the precision and stability of the bacterial cell division machinery in a switch-like manner.","lang":"eng"}],"acknowledged_ssus":[{"_id":"LifeSc"},{"_id":"Bio"}],"oa_version":"Published Version","volume":10,"related_material":{"record":[{"relation":"dissertation_contains","id":"8358","status":"public"}]},"ec_funded":1,"publication_identifier":{"issn":["2041-1723"]},"publication_status":"published","file":[{"creator":"dernst","date_updated":"2020-07-14T12:47:53Z","file_size":8488733,"date_created":"2019-12-23T07:34:56Z","file_name":"2019_NatureComm_Caldas.pdf","access_level":"open_access","relation":"main_file","content_type":"application/pdf","file_id":"7208","checksum":"a1b44b427ba341383197790d0e8789fa"}],"language":[{"iso":"eng"}]},{"_id":"6069","type":"journal_article","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"status":"public","date_updated":"2023-09-08T11:39:02Z","ddc":["530","532"],"department":[{"_id":"BjHo"}],"file_date_updated":"2020-07-14T12:47:18Z","abstract":[{"text":"Electron transport in two-dimensional conducting materials such as graphene, with dominant electron–electron interaction, exhibits unusual vortex flow that leads to a nonlocal current-field relation (negative resistance), distinct from the classical Ohm’s law. The transport behavior of these materials is best described by low Reynolds number hydrodynamics, where the constitutive pressure–speed relation is Stoke’s law. Here we report evidence of such vortices observed in a viscous flow of Newtonian fluid in a microfluidic device consisting of a rectangular cavity—analogous to the electronic system. We extend our experimental observations to elliptic cavities of different eccentricities, and validate them by numerically solving bi-harmonic equation obtained for the viscous flow with no-slip boundary conditions. We verify the existence of a predicted threshold at which vortices appear. Strikingly, we find that a two-dimensional theoretical model captures the essential features of three-dimensional Stokes flow in experiments.","lang":"eng"}],"oa_version":"Published Version","scopus_import":"1","month":"02","intvolume":" 10","publication_identifier":{"issn":["2041-1723"]},"publication_status":"published","file":[{"creator":"dernst","file_size":2646391,"date_updated":"2020-07-14T12:47:18Z","file_name":"2019_NatureComm_Mayzel.pdf","date_created":"2019-03-05T13:33:04Z","relation":"main_file","access_level":"open_access","content_type":"application/pdf","checksum":"61192fc49e0d44907c2a4fe384e4b97f","file_id":"6070"}],"language":[{"iso":"eng"}],"volume":10,"ec_funded":1,"article_number":"937","project":[{"call_identifier":"H2020","_id":"260C2330-B435-11E9-9278-68D0E5697425","grant_number":"754411","name":"ISTplus - Postdoctoral Fellowships"}],"citation":{"mla":"Mayzel, Jonathan, et al. “Stokes Flow Analogous to Viscous Electron Current in Graphene.” Nature Communications, vol. 10, 937, Springer Nature, 2019, doi:10.1038/s41467-019-08916-5.","apa":"Mayzel, J., Steinberg, V., & Varshney, A. (2019). Stokes flow analogous to viscous electron current in graphene. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-019-08916-5","ama":"Mayzel J, Steinberg V, Varshney A. Stokes flow analogous to viscous electron current in graphene. Nature Communications. 2019;10. doi:10.1038/s41467-019-08916-5","short":"J. Mayzel, V. Steinberg, A. Varshney, Nature Communications 10 (2019).","ieee":"J. Mayzel, V. Steinberg, and A. Varshney, “Stokes flow analogous to viscous electron current in graphene,” Nature Communications, vol. 10. Springer Nature, 2019.","chicago":"Mayzel, Jonathan, Victor Steinberg, and Atul Varshney. “Stokes Flow Analogous to Viscous Electron Current in Graphene.” Nature Communications. Springer Nature, 2019. https://doi.org/10.1038/s41467-019-08916-5.","ista":"Mayzel J, Steinberg V, Varshney A. 2019. Stokes flow analogous to viscous electron current in graphene. Nature Communications. 10, 937."},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","author":[{"full_name":"Mayzel, Jonathan","last_name":"Mayzel","first_name":"Jonathan"},{"last_name":"Steinberg","full_name":"Steinberg, Victor","first_name":"Victor"},{"id":"2A2006B2-F248-11E8-B48F-1D18A9856A87","first_name":"Atul","last_name":"Varshney","full_name":"Varshney, Atul","orcid":"0000-0002-3072-5999"}],"article_processing_charge":"No","external_id":{"isi":["000459704600001"]},"title":"Stokes flow analogous to viscous electron current in graphene","quality_controlled":"1","publisher":"Springer Nature","oa":1,"isi":1,"has_accepted_license":"1","year":"2019","day":"26","publication":"Nature Communications","date_published":"2019-02-26T00:00:00Z","doi":"10.1038/s41467-019-08916-5","date_created":"2019-03-05T13:18:30Z"},{"article_number":"652","project":[{"name":"ISTplus - Postdoctoral Fellowships","grant_number":"754411","call_identifier":"H2020","_id":"260C2330-B435-11E9-9278-68D0E5697425"}],"citation":{"chicago":"Varshney, Atul, and Victor Steinberg. “Elastic Alfven Waves in Elastic Turbulence.” Nature Communications. Springer Nature, 2019. https://doi.org/10.1038/s41467-019-08551-0.","ista":"Varshney A, Steinberg V. 2019. Elastic alfven waves in elastic turbulence. Nature Communications. 10, 652.","mla":"Varshney, Atul, and Victor Steinberg. “Elastic Alfven Waves in Elastic Turbulence.” Nature Communications, vol. 10, 652, Springer Nature, 2019, doi:10.1038/s41467-019-08551-0.","apa":"Varshney, A., & Steinberg, V. (2019). Elastic alfven waves in elastic turbulence. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-019-08551-0","ama":"Varshney A, Steinberg V. Elastic alfven waves in elastic turbulence. Nature Communications. 2019;10. doi:10.1038/s41467-019-08551-0","short":"A. Varshney, V. Steinberg, Nature Communications 10 (2019).","ieee":"A. Varshney and V. Steinberg, “Elastic alfven waves in elastic turbulence,” Nature Communications, vol. 10. Springer Nature, 2019."},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","external_id":{"arxiv":["1902.03763"],"isi":["000458175300001"]},"article_processing_charge":"No","author":[{"first_name":"Atul","id":"2A2006B2-F248-11E8-B48F-1D18A9856A87","full_name":"Varshney, Atul","orcid":"0000-0002-3072-5999","last_name":"Varshney"},{"last_name":"Steinberg","full_name":"Steinberg, Victor","first_name":"Victor"}],"title":"Elastic alfven waves in elastic turbulence","oa":1,"publisher":"Springer Nature","quality_controlled":"1","year":"2019","isi":1,"has_accepted_license":"1","publication":"Nature Communications","day":"08","date_created":"2019-02-15T07:10:46Z","doi":"10.1038/s41467-019-08551-0","date_published":"2019-02-08T00:00:00Z","_id":"6014","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"type":"journal_article","article_type":"original","status":"public","date_updated":"2023-09-08T11:39:54Z","ddc":["530"],"department":[{"_id":"BjHo"}],"file_date_updated":"2020-07-14T12:47:17Z","abstract":[{"text":"Speed of sound waves in gases and liquids are governed by the compressibility of the medium. There exists another type of non-dispersive wave where the wave speed depends on stress instead of elasticity of the medium. A well-known example is the Alfven wave, which propagates through plasma permeated by a magnetic field with the speed determined by magnetic tension. An elastic analogue of Alfven waves has been predicted in a flow of dilute polymer solution where the elastic stress of the stretching polymers determines the elastic wave speed. Here we present quantitative evidence of elastic Alfven waves in elastic turbulence of a viscoelastic creeping flow between two obstacles in channel flow. The key finding in the experimental proof is a nonlinear dependence of the elastic wave speed cel on the Weissenberg number Wi, which deviates from predictions based on a model of linear polymer elasticity.","lang":"eng"}],"oa_version":"Published Version","scopus_import":"1","intvolume":" 10","month":"02","publication_status":"published","publication_identifier":{"issn":["2041-1723"]},"language":[{"iso":"eng"}],"file":[{"file_id":"6015","checksum":"d3acf07eaad95ec040d8e8565fc9ac37","content_type":"application/pdf","access_level":"open_access","relation":"main_file","date_created":"2019-02-15T07:15:00Z","file_name":"2019_NatureComm_Varshney.pdf","date_updated":"2020-07-14T12:47:17Z","file_size":1331490,"creator":"dernst"}],"ec_funded":1,"volume":10},{"day":"25","publication":"Physical Review E","isi":1,"year":"2019","date_published":"2019-07-25T00:00:00Z","doi":"10.1103/physreve.100.013112","date_created":"2019-08-09T09:40:41Z","quality_controlled":"1","publisher":"American Physical Society","oa":1,"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"chicago":"Suri, Balachandra, Ravi Kumar Pallantla, Michael F. Schatz, and Roman O. Grigoriev. “Heteroclinic and Homoclinic Connections in a Kolmogorov-like Flow.” Physical Review E. American Physical Society, 2019. https://doi.org/10.1103/physreve.100.013112.","ista":"Suri B, Pallantla RK, Schatz MF, Grigoriev RO. 2019. Heteroclinic and homoclinic connections in a Kolmogorov-like flow. Physical Review E. 100(1), 013112.","mla":"Suri, Balachandra, et al. “Heteroclinic and Homoclinic Connections in a Kolmogorov-like Flow.” Physical Review E, vol. 100, no. 1, 013112, American Physical Society, 2019, doi:10.1103/physreve.100.013112.","ama":"Suri B, Pallantla RK, Schatz MF, Grigoriev RO. Heteroclinic and homoclinic connections in a Kolmogorov-like flow. Physical Review E. 2019;100(1). doi:10.1103/physreve.100.013112","apa":"Suri, B., Pallantla, R. K., Schatz, M. F., & Grigoriev, R. O. (2019). Heteroclinic and homoclinic connections in a Kolmogorov-like flow. Physical Review E. American Physical Society. https://doi.org/10.1103/physreve.100.013112","ieee":"B. Suri, R. K. Pallantla, M. F. Schatz, and R. O. Grigoriev, “Heteroclinic and homoclinic connections in a Kolmogorov-like flow,” Physical Review E, vol. 100, no. 1. American Physical Society, 2019.","short":"B. Suri, R.K. Pallantla, M.F. Schatz, R.O. Grigoriev, Physical Review E 100 (2019)."},"title":"Heteroclinic and homoclinic connections in a Kolmogorov-like flow","author":[{"first_name":"Balachandra","id":"47A5E706-F248-11E8-B48F-1D18A9856A87","full_name":"Suri, Balachandra","last_name":"Suri"},{"last_name":"Pallantla","full_name":"Pallantla, Ravi Kumar","first_name":"Ravi Kumar"},{"full_name":"Schatz, Michael F.","last_name":"Schatz","first_name":"Michael F."},{"first_name":"Roman O.","full_name":"Grigoriev, Roman O.","last_name":"Grigoriev"}],"article_processing_charge":"No","external_id":{"isi":["000477911800012"],"arxiv":["1907.05860"]},"article_number":"013112","project":[{"_id":"25681D80-B435-11E9-9278-68D0E5697425","call_identifier":"FP7","grant_number":"291734","name":"International IST Postdoc Fellowship Programme"}],"language":[{"iso":"eng"}],"publication_identifier":{"eissn":["2470-0053"],"issn":["2470-0045"]},"publication_status":"published","issue":"1","volume":100,"ec_funded":1,"oa_version":"Preprint","abstract":[{"text":"Recent studies suggest that unstable recurrent solutions of the Navier-Stokes equation provide new insights\r\ninto dynamics of turbulent flows. In this study, we compute an extensive network of dynamical connections\r\nbetween such solutions in a weakly turbulent quasi-two-dimensional Kolmogorov flow that lies in the inversion symmetric subspace. In particular, we find numerous isolated heteroclinic connections between different\r\ntypes of solutions—equilibria, periodic, and quasiperiodic orbits—as well as continua of connections forming\r\nhigher-dimensional connecting manifolds. We also compute a homoclinic connection of a periodic orbit and\r\nprovide strong evidence that the associated homoclinic tangle forms the chaotic repeller that underpins transient\r\nturbulence in the symmetric subspace.","lang":"eng"}],"month":"07","intvolume":" 100","scopus_import":"1","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1907.05860"}],"ddc":["532"],"date_updated":"2024-02-28T13:13:00Z","department":[{"_id":"BjHo"}],"_id":"6779","status":"public","article_type":"original","type":"journal_article"},{"_id":"6486","status":"public","article_type":"original","type":"journal_article","date_updated":"2024-03-27T23:30:35Z","department":[{"_id":"BjHo"}],"oa_version":"Preprint","acknowledged_ssus":[{"_id":"M-Shop"}],"abstract":[{"lang":"eng","text":"Based on a novel control scheme, where a steady modification of the streamwise velocity profile leads to complete relaminarization of initially fully turbulent pipe flow, we investigate the applicability and usefulness of custom-shaped honeycombs for such control. The custom-shaped honeycombs are used as stationary flow management devices which generate specific modifications of the streamwise velocity profile. Stereoscopic particle image velocimetry and pressure drop measurements are used to investigate and capture the development of the relaminarizing flow downstream these devices. We compare the performance of straight (constant length across the radius of the pipe) honeycombs with custom-shaped ones (variable length across the radius) and try to determine the optimal shape for maximal relaminarization at minimal pressure loss. The optimally modified streamwise velocity profile is found to be M-shaped, and the maximum attainable Reynolds number for total relaminarization is found to be of the order of 10,000. Consequently, the respective reduction in skin friction downstream of the device is almost by a factor of 5. The break-even point, where the additional pressure drop caused by the device is balanced by the savings due to relaminarization and a net gain is obtained, corresponds to a downstream stretch of distances as low as approximately 100 pipe diameters of laminar flow."}],"month":"11","intvolume":" 141","scopus_import":"1","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1809.07625"}],"language":[{"iso":"eng"}],"publication_identifier":{"issn":["00982202"],"eissn":["1528901X"]},"publication_status":"published","issue":"11","related_material":{"record":[{"id":"7258","status":"public","relation":"dissertation_contains"}]},"volume":141,"ec_funded":1,"article_number":"111105","project":[{"name":"Decoding the complexity of turbulence at its origin","grant_number":"306589","call_identifier":"FP7","_id":"25152F3A-B435-11E9-9278-68D0E5697425"}],"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"mla":"Kühnen, Jakob, et al. “Relaminarization of Pipe Flow by Means of 3D-Printed Shaped Honeycombs.” Journal of Fluids Engineering, vol. 141, no. 11, 111105, ASME, 2019, doi:10.1115/1.4043494.","short":"J. Kühnen, D. Scarselli, B. Hof, Journal of Fluids Engineering 141 (2019).","ieee":"J. Kühnen, D. Scarselli, and B. Hof, “Relaminarization of pipe flow by means of 3D-printed shaped honeycombs,” Journal of Fluids Engineering, vol. 141, no. 11. ASME, 2019.","apa":"Kühnen, J., Scarselli, D., & Hof, B. (2019). Relaminarization of pipe flow by means of 3D-printed shaped honeycombs. Journal of Fluids Engineering. ASME. https://doi.org/10.1115/1.4043494","ama":"Kühnen J, Scarselli D, Hof B. Relaminarization of pipe flow by means of 3D-printed shaped honeycombs. Journal of Fluids Engineering. 2019;141(11). doi:10.1115/1.4043494","chicago":"Kühnen, Jakob, Davide Scarselli, and Björn Hof. “Relaminarization of Pipe Flow by Means of 3D-Printed Shaped Honeycombs.” Journal of Fluids Engineering. ASME, 2019. https://doi.org/10.1115/1.4043494.","ista":"Kühnen J, Scarselli D, Hof B. 2019. Relaminarization of pipe flow by means of 3D-printed shaped honeycombs. Journal of Fluids Engineering. 141(11), 111105."},"title":"Relaminarization of pipe flow by means of 3D-printed shaped honeycombs","author":[{"full_name":"Kühnen, Jakob","orcid":"0000-0003-4312-0179","last_name":"Kühnen","id":"3A47AE32-F248-11E8-B48F-1D18A9856A87","first_name":"Jakob"},{"id":"40315C30-F248-11E8-B48F-1D18A9856A87","first_name":"Davide","last_name":"Scarselli","full_name":"Scarselli, Davide","orcid":"0000-0001-5227-4271"},{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","last_name":"Hof","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn"}],"external_id":{"arxiv":["1809.07625"],"isi":["000487748600005"]},"article_processing_charge":"No","quality_controlled":"1","publisher":"ASME","oa":1,"day":"01","publication":"Journal of Fluids Engineering","isi":1,"year":"2019","date_published":"2019-11-01T00:00:00Z","doi":"10.1115/1.4043494","date_created":"2019-05-26T21:59:13Z"},{"oa_version":"Preprint","abstract":[{"text":"Following the recent observation that turbulent pipe flow can be relaminarised bya relatively simple modification of the mean velocity profile, we here carry out aquantitative experimental investigation of this phenomenon. Our study confirms thata flat velocity profile leads to a collapse of turbulence and in order to achieve theblunted profile shape, we employ a moving pipe segment that is briefly and rapidlyshifted in the streamwise direction. The relaminarisation threshold and the minimumshift length and speeds are determined as a function of Reynolds number. Althoughturbulence is still active after the acceleration phase, the modulated profile possessesa severely decreased lift-up potential as measured by transient growth. As shown,this results in an exponential decay of fluctuations and the flow relaminarises. Whilethis method can be easily applied at low to moderate flow speeds, the minimumstreamwise length over which the acceleration needs to act increases linearly with theReynolds number.","lang":"eng"}],"intvolume":" 867","month":"05","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1807.05357"}],"scopus_import":"1","language":[{"iso":"eng"}],"publication_status":"published","publication_identifier":{"issn":["00221120"],"eissn":["14697645"]},"ec_funded":1,"related_material":{"record":[{"relation":"dissertation_contains","status":"public","id":"7258"}],"link":[{"relation":"supplementary_material","url":"https://doi.org/10.1017/jfm.2019.191"}]},"volume":867,"_id":"6228","status":"public","type":"journal_article","date_updated":"2024-03-27T23:30:35Z","department":[{"_id":"BjHo"}],"oa":1,"quality_controlled":"1","publisher":"Cambridge University Press","publication":"Journal of Fluid Mechanics","day":"25","year":"2019","isi":1,"date_created":"2019-04-07T21:59:14Z","doi":"10.1017/jfm.2019.191","date_published":"2019-05-25T00:00:00Z","page":"934-948","project":[{"call_identifier":"FP7","_id":"25152F3A-B435-11E9-9278-68D0E5697425","grant_number":"306589","name":"Decoding the complexity of turbulence at its origin"},{"_id":"25104D44-B435-11E9-9278-68D0E5697425","call_identifier":"H2020","name":"Eliminating turbulence in oil pipelines","grant_number":"737549"}],"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","citation":{"mla":"Scarselli, Davide, et al. “Relaminarising Pipe Flow by Wall Movement.” Journal of Fluid Mechanics, vol. 867, Cambridge University Press, 2019, pp. 934–48, doi:10.1017/jfm.2019.191.","short":"D. Scarselli, J. Kühnen, B. Hof, Journal of Fluid Mechanics 867 (2019) 934–948.","ieee":"D. Scarselli, J. Kühnen, and B. Hof, “Relaminarising pipe flow by wall movement,” Journal of Fluid Mechanics, vol. 867. Cambridge University Press, pp. 934–948, 2019.","apa":"Scarselli, D., Kühnen, J., & Hof, B. (2019). Relaminarising pipe flow by wall movement. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2019.191","ama":"Scarselli D, Kühnen J, Hof B. Relaminarising pipe flow by wall movement. Journal of Fluid Mechanics. 2019;867:934-948. doi:10.1017/jfm.2019.191","chicago":"Scarselli, Davide, Jakob Kühnen, and Björn Hof. “Relaminarising Pipe Flow by Wall Movement.” Journal of Fluid Mechanics. Cambridge University Press, 2019. https://doi.org/10.1017/jfm.2019.191.","ista":"Scarselli D, Kühnen J, Hof B. 2019. Relaminarising pipe flow by wall movement. Journal of Fluid Mechanics. 867, 934–948."},"title":"Relaminarising pipe flow by wall movement","article_processing_charge":"No","external_id":{"arxiv":["1807.05357"],"isi":["000462606100001"]},"author":[{"id":"40315C30-F248-11E8-B48F-1D18A9856A87","first_name":"Davide","orcid":"0000-0001-5227-4271","full_name":"Scarselli, Davide","last_name":"Scarselli"},{"last_name":"Kühnen","full_name":"Kühnen, Jakob","orcid":"0000-0003-4312-0179","first_name":"Jakob","id":"3A47AE32-F248-11E8-B48F-1D18A9856A87"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","last_name":"Hof","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn"}]},{"_id":"6508","article_type":"original","type":"journal_article","status":"public","date_updated":"2024-03-27T23:30:38Z","ddc":["570"],"file_date_updated":"2020-10-21T07:22:34Z","department":[{"_id":"CaHe"},{"_id":"EdHa"},{"_id":"BjHo"}],"acknowledged_ssus":[{"_id":"Bio"},{"_id":"PreCl"}],"abstract":[{"lang":"eng","text":"Segregation of maternal determinants within the oocyte constitutes the first step in embryo patterning. In zebrafish oocytes, extensive ooplasmic streaming leads to the segregation of ooplasm from yolk granules along the animal-vegetal axis of the oocyte. Here, we show that this process does not rely on cortical actin reorganization, as previously thought, but instead on a cell-cycle-dependent bulk actin polymerization wave traveling from the animal to the vegetal pole of the oocyte. This wave functions in segregation by both pulling ooplasm animally and pushing yolk granules vegetally. Using biophysical experimentation and theory, we show that ooplasm pulling is mediated by bulk actin network flows exerting friction forces on the ooplasm, while yolk granule pushing is achieved by a mechanism closely resembling actin comet formation on yolk granules. Our study defines a novel role of cell-cycle-controlled bulk actin polymerization waves in oocyte polarization via ooplasmic segregation."}],"oa_version":"Published Version","pmid":1,"scopus_import":"1","main_file_link":[{"url":"https://doi.org/10.1016/j.cell.2019.04.030","open_access":"1"}],"month":"05","intvolume":" 177","publication_identifier":{"issn":["00928674"],"eissn":["10974172"]},"publication_status":"published","file":[{"file_name":"2019_Cell_Shamipour_accepted.pdf","date_created":"2020-10-21T07:22:34Z","creator":"dernst","file_size":3356292,"date_updated":"2020-10-21T07:22:34Z","success":1,"file_id":"8686","checksum":"aea43726d80e35ce3885073a5f05c3e3","relation":"main_file","access_level":"open_access","content_type":"application/pdf"}],"language":[{"iso":"eng"}],"issue":"6","related_material":{"record":[{"relation":"dissertation_contains","id":"8350","status":"public"}],"link":[{"relation":"press_release","url":"https://ist.ac.at/en/news/how-the-cytoplasm-separates-from-the-yolk/","description":"News on IST Homepage"}]},"volume":177,"ec_funded":1,"project":[{"call_identifier":"H2020","_id":"260F1432-B435-11E9-9278-68D0E5697425","grant_number":"742573","name":"Interaction and feedback between cell mechanics and fate specification in vertebrate gastrulation"},{"grant_number":"P31639","name":"Active mechano-chemical description of the cell cytoskeleton","_id":"268294B6-B435-11E9-9278-68D0E5697425","call_identifier":"FWF"}],"citation":{"mla":"Shamipour, Shayan, et al. “Bulk Actin Dynamics Drive Phase Segregation in Zebrafish Oocytes.” Cell, vol. 177, no. 6, Elsevier, 2019, p. 1463–1479.e18, doi:10.1016/j.cell.2019.04.030.","apa":"Shamipour, S., Kardos, R., Xue, S., Hof, B., Hannezo, E. B., & Heisenberg, C.-P. J. (2019). Bulk actin dynamics drive phase segregation in zebrafish oocytes. Cell. Elsevier. https://doi.org/10.1016/j.cell.2019.04.030","ama":"Shamipour S, Kardos R, Xue S, Hof B, Hannezo EB, Heisenberg C-PJ. Bulk actin dynamics drive phase segregation in zebrafish oocytes. Cell. 2019;177(6):1463-1479.e18. doi:10.1016/j.cell.2019.04.030","short":"S. Shamipour, R. Kardos, S. Xue, B. Hof, E.B. Hannezo, C.-P.J. Heisenberg, Cell 177 (2019) 1463–1479.e18.","ieee":"S. Shamipour, R. Kardos, S. Xue, B. Hof, E. B. Hannezo, and C.-P. J. Heisenberg, “Bulk actin dynamics drive phase segregation in zebrafish oocytes,” Cell, vol. 177, no. 6. Elsevier, p. 1463–1479.e18, 2019.","chicago":"Shamipour, Shayan, Roland Kardos, Shi-lei Xue, Björn Hof, Edouard B Hannezo, and Carl-Philipp J Heisenberg. “Bulk Actin Dynamics Drive Phase Segregation in Zebrafish Oocytes.” Cell. Elsevier, 2019. https://doi.org/10.1016/j.cell.2019.04.030.","ista":"Shamipour S, Kardos R, Xue S, Hof B, Hannezo EB, Heisenberg C-PJ. 2019. Bulk actin dynamics drive phase segregation in zebrafish oocytes. Cell. 177(6), 1463–1479.e18."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","author":[{"last_name":"Shamipour","full_name":"Shamipour, Shayan","first_name":"Shayan","id":"40B34FE2-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Roland","id":"4039350E-F248-11E8-B48F-1D18A9856A87","full_name":"Kardos, Roland","last_name":"Kardos"},{"first_name":"Shi-lei","id":"31D2C804-F248-11E8-B48F-1D18A9856A87","last_name":"Xue","full_name":"Xue, Shi-lei"},{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof"},{"full_name":"Hannezo, Edouard B","orcid":"0000-0001-6005-1561","last_name":"Hannezo","first_name":"Edouard B","id":"3A9DB764-F248-11E8-B48F-1D18A9856A87"},{"id":"39427864-F248-11E8-B48F-1D18A9856A87","first_name":"Carl-Philipp J","orcid":"0000-0002-0912-4566","full_name":"Heisenberg, Carl-Philipp J","last_name":"Heisenberg"}],"external_id":{"pmid":["31080065"],"isi":["000469415100013"]},"article_processing_charge":"No","title":"Bulk actin dynamics drive phase segregation in zebrafish oocytes","acknowledgement":"We would like to thank Pierre Recho, Guillaume Salbreux, and Silvia Grigolon for advice on the theory, Lila Solnica-Krezel for kindly providing us with zebrafish dachsous mutants, members of the Heisenberg and Hannezo groups for fruitful discussions, and the Bioimaging and zebrafish facilities at IST Austria for their continuous support. This project has received funding from the European Union (European Research Council Advanced Grant 742573 to C.P.H.) and from the Austrian Science Fund (FWF) (P 31639 to E.H.).","quality_controlled":"1","publisher":"Elsevier","oa":1,"isi":1,"has_accepted_license":"1","year":"2019","day":"30","publication":"Cell","page":"1463-1479.e18","doi":"10.1016/j.cell.2019.04.030","date_published":"2019-05-30T00:00:00Z","date_created":"2019-06-02T21:59:12Z"},{"citation":{"short":"C. Schwayer, S. Shamipour, K. Pranjic-Ferscha, A. Schauer, M. Balda, M. Tada, K. Matter, C.-P.J. Heisenberg, Cell 179 (2019) 937–952.e18.","ieee":"C. Schwayer et al., “Mechanosensation of tight junctions depends on ZO-1 phase separation and flow,” Cell, vol. 179, no. 4. Cell Press, p. 937–952.e18, 2019.","ama":"Schwayer C, Shamipour S, Pranjic-Ferscha K, et al. Mechanosensation of tight junctions depends on ZO-1 phase separation and flow. Cell. 2019;179(4):937-952.e18. doi:10.1016/j.cell.2019.10.006","apa":"Schwayer, C., Shamipour, S., Pranjic-Ferscha, K., Schauer, A., Balda, M., Tada, M., … Heisenberg, C.-P. J. (2019). Mechanosensation of tight junctions depends on ZO-1 phase separation and flow. Cell. Cell Press. https://doi.org/10.1016/j.cell.2019.10.006","mla":"Schwayer, Cornelia, et al. “Mechanosensation of Tight Junctions Depends on ZO-1 Phase Separation and Flow.” Cell, vol. 179, no. 4, Cell Press, 2019, p. 937–952.e18, doi:10.1016/j.cell.2019.10.006.","ista":"Schwayer C, Shamipour S, Pranjic-Ferscha K, Schauer A, Balda M, Tada M, Matter K, Heisenberg C-PJ. 2019. Mechanosensation of tight junctions depends on ZO-1 phase separation and flow. Cell. 179(4), 937–952.e18.","chicago":"Schwayer, Cornelia, Shayan Shamipour, Kornelija Pranjic-Ferscha, Alexandra Schauer, M Balda, M Tada, K Matter, and Carl-Philipp J Heisenberg. “Mechanosensation of Tight Junctions Depends on ZO-1 Phase Separation and Flow.” Cell. Cell Press, 2019. https://doi.org/10.1016/j.cell.2019.10.006."},"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","author":[{"full_name":"Schwayer, Cornelia","orcid":"0000-0001-5130-2226","last_name":"Schwayer","id":"3436488C-F248-11E8-B48F-1D18A9856A87","first_name":"Cornelia"},{"full_name":"Shamipour, Shayan","last_name":"Shamipour","id":"40B34FE2-F248-11E8-B48F-1D18A9856A87","first_name":"Shayan"},{"last_name":"Pranjic-Ferscha","full_name":"Pranjic-Ferscha, Kornelija","first_name":"Kornelija","id":"4362B3C2-F248-11E8-B48F-1D18A9856A87"},{"id":"30A536BA-F248-11E8-B48F-1D18A9856A87","first_name":"Alexandra","last_name":"Schauer","full_name":"Schauer, Alexandra","orcid":"0000-0001-7659-9142"},{"last_name":"Balda","full_name":"Balda, M","first_name":"M"},{"full_name":"Tada, M","last_name":"Tada","first_name":"M"},{"last_name":"Matter","full_name":"Matter, K","first_name":"K"},{"orcid":"0000-0002-0912-4566","full_name":"Heisenberg, Carl-Philipp J","last_name":"Heisenberg","id":"39427864-F248-11E8-B48F-1D18A9856A87","first_name":"Carl-Philipp J"}],"external_id":{"isi":["000493898000012"],"pmid":["31675500"]},"article_processing_charge":"No","title":"Mechanosensation of tight junctions depends on ZO-1 phase separation and flow","project":[{"name":"Interaction and feedback between cell mechanics and fate specification in vertebrate gastrulation","grant_number":"742573","_id":"260F1432-B435-11E9-9278-68D0E5697425","call_identifier":"H2020"}],"has_accepted_license":"1","isi":1,"year":"2019","day":"31","publication":"Cell","page":"937-952.e18","doi":"10.1016/j.cell.2019.10.006","date_published":"2019-10-31T00:00:00Z","date_created":"2019-11-12T12:51:06Z","quality_controlled":"1","publisher":"Cell Press","oa":1,"date_updated":"2024-03-27T23:30:38Z","ddc":["570"],"department":[{"_id":"CaHe"},{"_id":"BjHo"}],"file_date_updated":"2020-10-21T07:09:45Z","_id":"7001","article_type":"original","type":"journal_article","status":"public","publication_identifier":{"issn":["0092-8674"],"eissn":["1097-4172"]},"publication_status":"published","file":[{"relation":"main_file","access_level":"open_access","content_type":"application/pdf","success":1,"checksum":"33dac4bb77ee630e2666e936b4d57980","file_id":"8684","creator":"dernst","file_size":8805878,"date_updated":"2020-10-21T07:09:45Z","file_name":"2019_Cell_Schwayer_accepted.pdf","date_created":"2020-10-21T07:09:45Z"}],"language":[{"iso":"eng"}],"volume":179,"related_material":{"link":[{"description":"News auf IST Website","relation":"press_release","url":"https://ist.ac.at/en/news/biochemistry-meets-mechanics-the-sensitive-nature-of-cell-cell-contact-formation-in-embryo-development/"}],"record":[{"status":"public","id":"7186","relation":"dissertation_contains"},{"id":"8350","status":"public","relation":"dissertation_contains"}]},"issue":"4","ec_funded":1,"acknowledged_ssus":[{"_id":"PreCl"},{"_id":"Bio"}],"pmid":1,"oa_version":"Submitted Version","scopus_import":"1","month":"10","intvolume":" 179"},{"date_created":"2019-03-31T21:59:12Z","date_published":"2019-03-22T00:00:00Z","doi":"10.1103/PhysRevLett.122.114502","year":"2019","isi":1,"publication":"Physical Review Letters","day":"22","oa":1,"quality_controlled":"1","publisher":"American Physical Society","external_id":{"arxiv":["1809.06358"],"isi":["000461922000006"]},"article_processing_charge":"No","author":[{"last_name":"Agrawal","full_name":"Agrawal, Nishchal","id":"469E6004-F248-11E8-B48F-1D18A9856A87","first_name":"Nishchal"},{"first_name":"George H","id":"448BD5BC-F248-11E8-B48F-1D18A9856A87","last_name":"Choueiri","full_name":"Choueiri, George H"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof"}],"title":"Transition to turbulence in particle laden flows","citation":{"short":"N. Agrawal, G.H. Choueiri, B. Hof, Physical Review Letters 122 (2019).","ieee":"N. Agrawal, G. H. Choueiri, and B. Hof, “Transition to turbulence in particle laden flows,” Physical Review Letters, vol. 122, no. 11. American Physical Society, 2019.","ama":"Agrawal N, Choueiri GH, Hof B. Transition to turbulence in particle laden flows. Physical Review Letters. 2019;122(11). doi:10.1103/PhysRevLett.122.114502","apa":"Agrawal, N., Choueiri, G. H., & Hof, B. (2019). Transition to turbulence in particle laden flows. Physical Review Letters. American Physical Society. https://doi.org/10.1103/PhysRevLett.122.114502","mla":"Agrawal, Nishchal, et al. “Transition to Turbulence in Particle Laden Flows.” Physical Review Letters, vol. 122, no. 11, 114502, American Physical Society, 2019, doi:10.1103/PhysRevLett.122.114502.","ista":"Agrawal N, Choueiri GH, Hof B. 2019. Transition to turbulence in particle laden flows. Physical Review Letters. 122(11), 114502.","chicago":"Agrawal, Nishchal, George H Choueiri, and Björn Hof. “Transition to Turbulence in Particle Laden Flows.” Physical Review Letters. American Physical Society, 2019. https://doi.org/10.1103/PhysRevLett.122.114502."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","article_number":"114502","volume":122,"issue":"11","related_material":{"record":[{"id":"9728","status":"public","relation":"dissertation_contains"}]},"publication_status":"published","publication_identifier":{"issn":["00319007"],"eissn":["10797114"]},"language":[{"iso":"eng"}],"main_file_link":[{"url":"https://arxiv.org/abs/1809.06358","open_access":"1"}],"scopus_import":"1","intvolume":" 122","month":"03","abstract":[{"lang":"eng","text":"Suspended particles can alter the properties of fluids and in particular also affect the transition fromlaminar to turbulent flow. An earlier study [Mataset al.,Phys. Rev. Lett.90, 014501 (2003)] reported howthe subcritical (i.e., hysteretic) transition to turbulent puffs is affected by the addition of particles. Here weshow that in addition to this known transition, with increasing concentration a supercritical (i.e.,continuous) transition to a globally fluctuating state is found. At the same time the Newtonian-typetransition to puffs is delayed to larger Reynolds numbers. At even higher concentration only the globallyfluctuating state is found. The dynamics of particle laden flows are hence determined by two competinginstabilities that give rise to three flow regimes: Newtonian-type turbulence at low, a particle inducedglobally fluctuating state at high, and a coexistence state at intermediate concentrations."}],"oa_version":"Preprint","department":[{"_id":"BjHo"}],"date_updated":"2024-03-27T23:30:47Z","type":"journal_article","status":"public","_id":"6189"},{"type":"journal_article","status":"public","_id":"291","department":[{"_id":"BjHo"}],"date_updated":"2023-09-11T12:45:44Z","scopus_import":"1","main_file_link":[{"url":"https://arxiv.org/abs/1802.01918","open_access":"1"}],"month":"05","intvolume":" 3","abstract":[{"lang":"eng","text":"Over the past decade, the edge of chaos has proven to be a fruitful starting point for investigations of shear flows when the laminar base flow is linearly stable. Numerous computational studies of shear flows demonstrated the existence of states that separate laminar and turbulent regions of the state space. In addition, some studies determined invariant solutions that reside on this edge. In this paper, we study the unstable manifold of one such solution with the aid of continuous symmetry reduction, which we formulate here for the simultaneous quotiening of axial and azimuthal symmetries. Upon our investigation of the unstable manifold, we discover a previously unknown traveling-wave solution on the laminar-turbulent boundary with a relatively complex structure. By means of low-dimensional projections, we visualize different dynamical paths that connect these solutions to the turbulence. Our numerical experiments demonstrate that the laminar-turbulent boundary exhibits qualitatively different regions whose properties are influenced by the nearby invariant solutions."}],"oa_version":"Preprint","issue":"5","volume":3,"publication_status":"published","language":[{"iso":"eng"}],"article_number":"054401","publist_id":"7590","author":[{"id":"3EA1010E-F248-11E8-B48F-1D18A9856A87","first_name":"Nazmi B","last_name":"Budanur","orcid":"0000-0003-0423-5010","full_name":"Budanur, Nazmi B"},{"last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn"}],"external_id":{"arxiv":["1802.01918"],"isi":["000433426200001"]},"article_processing_charge":"No","title":"Complexity of the laminar-turbulent boundary in pipe flow","citation":{"ieee":"N. B. Budanur and B. Hof, “Complexity of the laminar-turbulent boundary in pipe flow,” Physical Review Fluids, vol. 3, no. 5. American Physical Society, 2018.","short":"N.B. Budanur, B. Hof, Physical Review Fluids 3 (2018).","apa":"Budanur, N. B., & Hof, B. (2018). Complexity of the laminar-turbulent boundary in pipe flow. Physical Review Fluids. American Physical Society. https://doi.org/10.1103/PhysRevFluids.3.054401","ama":"Budanur NB, Hof B. Complexity of the laminar-turbulent boundary in pipe flow. Physical Review Fluids. 2018;3(5). doi:10.1103/PhysRevFluids.3.054401","mla":"Budanur, Nazmi B., and Björn Hof. “Complexity of the Laminar-Turbulent Boundary in Pipe Flow.” Physical Review Fluids, vol. 3, no. 5, 054401, American Physical Society, 2018, doi:10.1103/PhysRevFluids.3.054401.","ista":"Budanur NB, Hof B. 2018. Complexity of the laminar-turbulent boundary in pipe flow. Physical Review Fluids. 3(5), 054401.","chicago":"Budanur, Nazmi B, and Björn Hof. “Complexity of the Laminar-Turbulent Boundary in Pipe Flow.” Physical Review Fluids. American Physical Society, 2018. https://doi.org/10.1103/PhysRevFluids.3.054401."},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","publisher":"American Physical Society","quality_controlled":"1","oa":1,"doi":"10.1103/PhysRevFluids.3.054401","date_published":"2018-05-30T00:00:00Z","date_created":"2018-12-11T11:45:39Z","isi":1,"year":"2018","day":"30","publication":"Physical Review Fluids"},{"has_accepted_license":"1","isi":1,"year":"2018","day":"15","publication":"Physical Review Fluids","date_published":"2018-10-15T00:00:00Z","doi":"10.1103/PhysRevFluids.3.103302","date_created":"2018-12-11T11:44:11Z","quality_controlled":"1","publisher":"American Physical Society","oa":1,"citation":{"short":"A. Varshney, V. Steinberg, Physical Review Fluids 3 (2018).","ieee":"A. Varshney and V. Steinberg, “Drag enhancement and drag reduction in viscoelastic flow,” Physical Review Fluids, vol. 3, no. 10. American Physical Society, 2018.","apa":"Varshney, A., & Steinberg, V. (2018). Drag enhancement and drag reduction in viscoelastic flow. Physical Review Fluids. American Physical Society. https://doi.org/10.1103/PhysRevFluids.3.103302","ama":"Varshney A, Steinberg V. Drag enhancement and drag reduction in viscoelastic flow. Physical Review Fluids. 2018;3(10). doi:10.1103/PhysRevFluids.3.103302","mla":"Varshney, Atul, and Victor Steinberg. “Drag Enhancement and Drag Reduction in Viscoelastic Flow.” Physical Review Fluids, vol. 3, no. 10, 103302, American Physical Society, 2018, doi:10.1103/PhysRevFluids.3.103302.","ista":"Varshney A, Steinberg V. 2018. Drag enhancement and drag reduction in viscoelastic flow. Physical Review Fluids. 3(10), 103302.","chicago":"Varshney, Atul, and Victor Steinberg. “Drag Enhancement and Drag Reduction in Viscoelastic Flow.” Physical Review Fluids. American Physical Society, 2018. https://doi.org/10.1103/PhysRevFluids.3.103302."},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","author":[{"orcid":"0000-0002-3072-5999","full_name":"Varshney, Atul","last_name":"Varshney","first_name":"Atul","id":"2A2006B2-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Victor","last_name":"Steinberg","full_name":"Steinberg, Victor"}],"publist_id":"8038","article_processing_charge":"No","external_id":{"isi":["000447311500001"]},"title":"Drag enhancement and drag reduction in viscoelastic flow","article_number":"103302 ","project":[{"_id":"260C2330-B435-11E9-9278-68D0E5697425","call_identifier":"H2020","grant_number":"754411","name":"ISTplus - Postdoctoral Fellowships"}],"publication_status":"published","file":[{"access_level":"open_access","relation":"main_file","content_type":"application/pdf","file_id":"4800","checksum":"e1445be33e8165114e96246275600750","creator":"system","date_updated":"2020-07-14T12:45:12Z","file_size":1409040,"date_created":"2018-12-12T10:10:14Z","file_name":"IST-2018-1061-v1+1_PhysRevFluids.3.103302.pdf"}],"language":[{"iso":"eng"}],"issue":"10","volume":3,"ec_funded":1,"abstract":[{"lang":"eng","text":"Creeping flow of polymeric fluid without inertia exhibits elastic instabilities and elastic turbulence accompanied by drag enhancement due to elastic stress produced by flow-stretched polymers. However, in inertia-dominated flow at high Re and low fluid elasticity El, a reduction in turbulent frictional drag is caused by an intricate competition between inertial and elastic stresses. Here we explore the effect of inertia on the stability of viscoelastic flow in a broad range of control parameters El and (Re,Wi). We present the stability diagram of observed flow regimes in Wi-Re coordinates and find that the instabilities' onsets show an unexpectedly nonmonotonic dependence on El. Further, three distinct regions in the diagram are identified based on El. Strikingly, for high-elasticity fluids we discover a complete relaminarization of flow at Reynolds number in the range of 1 to 10, different from a well-known turbulent drag reduction. These counterintuitive effects may be explained by a finite polymer extensibility and a suppression of vorticity at high Wi. Our results call for further theoretical and numerical development to uncover the role of inertial effect on elastic turbulence in a viscoelastic flow."}],"oa_version":"Published Version","scopus_import":"1","month":"10","intvolume":" 3","date_updated":"2023-09-11T12:59:28Z","ddc":["532"],"file_date_updated":"2020-07-14T12:45:12Z","department":[{"_id":"BjHo"}],"_id":"17","type":"journal_article","status":"public","pubrep_id":"1061"},{"volume":3,"issue":"10","ec_funded":1,"file":[{"access_level":"open_access","relation":"main_file","content_type":"application/pdf","file_id":"5043","checksum":"7fc0a2322214d1c04debef36d5bf2e8a","creator":"system","date_updated":"2020-07-14T12:45:04Z","file_size":1838431,"date_created":"2018-12-12T10:13:56Z","file_name":"IST-2018-1062-v1+1_PhysRevFluids.3.103303.pdf"}],"language":[{"iso":"eng"}],"publication_status":"published","month":"10","intvolume":" 3","scopus_import":"1","oa_version":"Submitted Version","abstract":[{"lang":"eng","text":"We report quantitative evidence of mixing-layer elastic instability in a viscoelastic fluid flow between two widely spaced obstacles hindering a channel flow at Re 1 and Wi 1. Two mixing layers with nonuniform shear velocity profiles are formed in the region between the obstacles. The mixing-layer instability arises in the vicinity of an inflection point on the shear velocity profile with a steep variation in the elastic stress. The instability results in an intermittent appearance of small vortices in the mixing layers and an amplification of spatiotemporal averaged vorticity in the elastic turbulence regime. The latter is characterized through scaling of friction factor with Wi and both pressure and velocity spectra. Furthermore, the observations reported provide improved understanding of the stability of the mixing layer in a viscoelastic fluid at large elasticity, i.e., Wi 1 and Re 1 and oppose the current view of suppression of vorticity solely by polymer additives."}],"file_date_updated":"2020-07-14T12:45:04Z","department":[{"_id":"BjHo"}],"ddc":["532"],"date_updated":"2023-09-13T08:57:05Z","status":"public","pubrep_id":"1062","type":"journal_article","article_type":"original","_id":"16","doi":"10.1103/PhysRevFluids.3.103303","date_published":"2018-10-16T00:00:00Z","date_created":"2018-12-11T11:44:10Z","day":"16","publication":"Physical Review Fluids","has_accepted_license":"1","isi":1,"year":"2018","publisher":"American Physical Society","quality_controlled":"1","oa":1,"acknowledgement":"This work was partially supported by the Israel Science Foundation (ISF; Grant No. 882/15) and the Binational USA-Israel Foundation (BSF; Grant No. 2016145).","title":"Mixing layer instability and vorticity amplification in a creeping viscoelastic flow","publist_id":"8039","author":[{"id":"2A2006B2-F248-11E8-B48F-1D18A9856A87","first_name":"Atul","last_name":"Varshney","orcid":"0000-0002-3072-5999","full_name":"Varshney, Atul"},{"full_name":"Steinberg, Victor","last_name":"Steinberg","first_name":"Victor"}],"external_id":{"isi":["000447469200001"]},"article_processing_charge":"No","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"mla":"Varshney, Atul, and Victor Steinberg. “Mixing Layer Instability and Vorticity Amplification in a Creeping Viscoelastic Flow.” Physical Review Fluids, vol. 3, no. 10, 103303, American Physical Society, 2018, doi:10.1103/PhysRevFluids.3.103303.","ama":"Varshney A, Steinberg V. Mixing layer instability and vorticity amplification in a creeping viscoelastic flow. Physical Review Fluids. 2018;3(10). doi:10.1103/PhysRevFluids.3.103303","apa":"Varshney, A., & Steinberg, V. (2018). Mixing layer instability and vorticity amplification in a creeping viscoelastic flow. Physical Review Fluids. American Physical Society. https://doi.org/10.1103/PhysRevFluids.3.103303","short":"A. Varshney, V. Steinberg, Physical Review Fluids 3 (2018).","ieee":"A. Varshney and V. Steinberg, “Mixing layer instability and vorticity amplification in a creeping viscoelastic flow,” Physical Review Fluids, vol. 3, no. 10. American Physical Society, 2018.","chicago":"Varshney, Atul, and Victor Steinberg. “Mixing Layer Instability and Vorticity Amplification in a Creeping Viscoelastic Flow.” Physical Review Fluids. American Physical Society, 2018. https://doi.org/10.1103/PhysRevFluids.3.103303.","ista":"Varshney A, Steinberg V. 2018. Mixing layer instability and vorticity amplification in a creeping viscoelastic flow. Physical Review Fluids. 3(10), 103303."},"project":[{"call_identifier":"H2020","_id":"260C2330-B435-11E9-9278-68D0E5697425","grant_number":"754411","name":"ISTplus - Postdoctoral Fellowships"}],"article_number":"103303"},{"oa":1,"quality_controlled":"1","publisher":"Elsevier","acknowledgement":"S.Altmeyer is a Serra Húnter Fellow","date_created":"2018-12-11T11:46:56Z","date_published":"2018-04-15T00:00:00Z","doi":"10.1016/j.jmmm.2017.12.073","page":"427 - 441","publication":"Journal of Magnetism and Magnetic Materials","day":"15","year":"2018","has_accepted_license":"1","isi":1,"title":"Non-linear dynamics and alternating ‘flip’ solutions in ferrofluidic Taylor-Couette flow","article_processing_charge":"No","external_id":{"isi":["000425547700061"]},"author":[{"orcid":"0000-0001-5964-0203","full_name":"Altmeyer, Sebastian","last_name":"Altmeyer","id":"2EE67FDC-F248-11E8-B48F-1D18A9856A87","first_name":"Sebastian"}],"publist_id":"7297","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"ista":"Altmeyer S. 2018. Non-linear dynamics and alternating ‘flip’ solutions in ferrofluidic Taylor-Couette flow. Journal of Magnetism and Magnetic Materials. 452, 427–441.","chicago":"Altmeyer, Sebastian. “Non-Linear Dynamics and Alternating ‘Flip’ Solutions in Ferrofluidic Taylor-Couette Flow.” Journal of Magnetism and Magnetic Materials. Elsevier, 2018. https://doi.org/10.1016/j.jmmm.2017.12.073.","short":"S. Altmeyer, Journal of Magnetism and Magnetic Materials 452 (2018) 427–441.","ieee":"S. Altmeyer, “Non-linear dynamics and alternating ‘flip’ solutions in ferrofluidic Taylor-Couette flow,” Journal of Magnetism and Magnetic Materials, vol. 452. Elsevier, pp. 427–441, 2018.","ama":"Altmeyer S. Non-linear dynamics and alternating ‘flip’ solutions in ferrofluidic Taylor-Couette flow. Journal of Magnetism and Magnetic Materials. 2018;452:427-441. doi:10.1016/j.jmmm.2017.12.073","apa":"Altmeyer, S. (2018). Non-linear dynamics and alternating ‘flip’ solutions in ferrofluidic Taylor-Couette flow. Journal of Magnetism and Magnetic Materials. Elsevier. https://doi.org/10.1016/j.jmmm.2017.12.073","mla":"Altmeyer, Sebastian. “Non-Linear Dynamics and Alternating ‘Flip’ Solutions in Ferrofluidic Taylor-Couette Flow.” Journal of Magnetism and Magnetic Materials, vol. 452, Elsevier, 2018, pp. 427–41, doi:10.1016/j.jmmm.2017.12.073."},"intvolume":" 452","month":"04","scopus_import":"1","oa_version":"Submitted Version","abstract":[{"lang":"eng","text":"This study treats with the influence of a symmetry-breaking transversal magnetic field on the nonlinear dynamics of ferrofluidic Taylor-Couette flow – flow confined between two concentric independently rotating cylinders. We detected alternating ‘flip’ solutions which are flow states featuring typical characteristics of slow-fast-dynamics in dynamical systems. The flip corresponds to a temporal change in the axial wavenumber and we find them to appear either as pure 2-fold axisymmetric (due to the symmetry-breaking nature of the applied transversal magnetic field) or involving non-axisymmetric, helical modes in its interim solution. The latter ones show features of typical ribbon solutions. In any case the flip solutions have a preferential first axial wavenumber which corresponds to the more stable state (slow dynamics) and second axial wavenumber, corresponding to the short appearing more unstable state (fast dynamics). However, in both cases the flip time grows exponential with increasing the magnetic field strength before the flip solutions, living on 2-tori invariant manifolds, cease to exist, with lifetime going to infinity. Further we show that ferrofluidic flow turbulence differ from the classical, ordinary (usually at high Reynolds number) turbulence. The applied magnetic field hinders the free motion of ferrofluid partials and therefore smoothen typical turbulent quantities and features so that speaking of mildly chaotic dynamics seems to be a more appropriate expression for the observed motion. "}],"volume":452,"language":[{"iso":"eng"}],"file":[{"file_size":17309535,"date_updated":"2020-07-14T12:46:37Z","creator":"dernst","file_name":"2018_Magnetism_Altmeyer.pdf","date_created":"2020-05-14T14:41:17Z","content_type":"application/pdf","relation":"main_file","access_level":"open_access","file_id":"7838","checksum":"431f5cd4a628d7ca21161f82b14ccb4f"}],"publication_status":"published","status":"public","article_type":"original","type":"journal_article","_id":"519","file_date_updated":"2020-07-14T12:46:37Z","department":[{"_id":"BjHo"}],"ddc":["530"],"date_updated":"2023-09-13T09:03:44Z"},{"status":"public","article_type":"original","type":"journal_article","_id":"5996","department":[{"_id":"BjHo"}],"date_updated":"2023-09-19T14:37:49Z","month":"03","intvolume":" 839","scopus_import":"1","main_file_link":[{"url":"https://arxiv.org/abs/1709.06372","open_access":"1"}],"oa_version":"Preprint","abstract":[{"lang":"eng","text":"In pipes, turbulence sets in despite the linear stability of the laminar Hagen–Poiseuille flow. The Reynolds number ( ) for which turbulence first appears in a given experiment – the ‘natural transition point’ – depends on imperfections of the set-up, or, more precisely, on the magnitude of finite amplitude perturbations. At onset, turbulence typically only occupies a certain fraction of the flow, and this fraction equally is found to differ from experiment to experiment. Despite these findings, Reynolds proposed that after sufficiently long times, flows may settle to steady conditions: below a critical velocity, flows should (regardless of initial conditions) always return to laminar, while above this velocity, eddying motion should persist. As will be shown, even in pipes several thousand diameters long, the spatio-temporal intermittent flow patterns observed at the end of the pipe strongly depend on the initial conditions, and there is no indication that different flow patterns would eventually settle to a (statistical) steady state. Exploiting the fact that turbulent puffs do not age (i.e. they are memoryless), we continuously recreate the puff sequence exiting the pipe at the pipe entrance, and in doing so introduce periodic boundary conditions for the puff pattern. This procedure allows us to study the evolution of the flow patterns for arbitrary long times, and we find that after times in excess of advective time units, indeed a statistical steady state is reached. Although the resulting flows remain spatio-temporally intermittent, puff splitting and decay rates eventually reach a balance, so that the turbulent fraction fluctuates around a well-defined level which only depends on . In accordance with Reynolds’ proposition, we find that at lower (here 2020), flows eventually always resume to laminar, while for higher ( ), turbulence persists. The critical point for pipe flow hence falls in the interval of $2020 , which is in very good agreement with the recently proposed value of . The latter estimate was based on single-puff statistics and entirely neglected puff interactions. Unlike in typical contact processes where such interactions strongly affect the percolation threshold, in pipe flow, the critical point is only marginally influenced. Interactions, on the other hand, are responsible for the approach to the statistical steady state. As shown, they strongly affect the resulting flow patterns, where they cause ‘puff clustering’, and these regions of large puff densities are observed to travel across the puff pattern in a wave-like fashion."}],"volume":839,"ec_funded":1,"language":[{"iso":"eng"}],"publication_identifier":{"eissn":["1469-7645"],"issn":["0022-1120"]},"publication_status":"published","project":[{"name":"Decoding the complexity of turbulence at its origin","grant_number":"306589","_id":"25152F3A-B435-11E9-9278-68D0E5697425","call_identifier":"FP7"}],"title":"The critical point of the transition to turbulence in pipe flow","author":[{"id":"3C5A959A-F248-11E8-B48F-1D18A9856A87","first_name":"Mukund","full_name":"Vasudevan, Mukund","last_name":"Vasudevan"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof"}],"article_processing_charge":"No","external_id":{"isi":["000437858300003"],"arxiv":["1709.06372"]},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"ama":"Vasudevan M, Hof B. The critical point of the transition to turbulence in pipe flow. Journal of Fluid Mechanics. 2018;839:76-94. doi:10.1017/jfm.2017.923","apa":"Vasudevan, M., & Hof, B. (2018). The critical point of the transition to turbulence in pipe flow. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2017.923","short":"M. Vasudevan, B. Hof, Journal of Fluid Mechanics 839 (2018) 76–94.","ieee":"M. Vasudevan and B. Hof, “The critical point of the transition to turbulence in pipe flow,” Journal of Fluid Mechanics, vol. 839. Cambridge University Press, pp. 76–94, 2018.","mla":"Vasudevan, Mukund, and Björn Hof. “The Critical Point of the Transition to Turbulence in Pipe Flow.” Journal of Fluid Mechanics, vol. 839, Cambridge University Press, 2018, pp. 76–94, doi:10.1017/jfm.2017.923.","ista":"Vasudevan M, Hof B. 2018. The critical point of the transition to turbulence in pipe flow. Journal of Fluid Mechanics. 839, 76–94.","chicago":"Vasudevan, Mukund, and Björn Hof. “The Critical Point of the Transition to Turbulence in Pipe Flow.” Journal of Fluid Mechanics. Cambridge University Press, 2018. https://doi.org/10.1017/jfm.2017.923."},"quality_controlled":"1","publisher":"Cambridge University Press","oa":1,"acknowledgement":" We also thank Philipp Maier and the IST Austria workshop for theirdedicated technical support","doi":"10.1017/jfm.2017.923","date_published":"2018-03-25T00:00:00Z","date_created":"2019-02-14T12:50:50Z","page":"76-94","day":"25","publication":"Journal of Fluid Mechanics","isi":1,"year":"2018"},{"date_created":"2018-12-11T11:45:51Z","date_published":"2018-03-19T00:00:00Z","doi":"10.1103/PhysRevLett.120.124501","publication":"Physical Review Letters","day":"19","year":"2018","isi":1,"oa":1,"publisher":"American Physical Society","quality_controlled":"1","acknowledgement":"The authors thank Philipp Maier and the IST Austria workshop for their dedicated technical support.","title":"Exceeding the asymptotic limit of polymer drag reduction","article_processing_charge":"No","external_id":{"isi":["000427804000005"]},"author":[{"first_name":"George H","id":"448BD5BC-F248-11E8-B48F-1D18A9856A87","full_name":"Choueiri, George H","last_name":"Choueiri"},{"last_name":"Lopez Alonso","full_name":"Lopez Alonso, Jose M","orcid":"0000-0002-0384-2022","first_name":"Jose M","id":"40770848-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Hof","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn"}],"publist_id":"7537","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"ieee":"G. H. Choueiri, J. M. Lopez Alonso, and B. Hof, “Exceeding the asymptotic limit of polymer drag reduction,” Physical Review Letters, vol. 120, no. 12. American Physical Society, 2018.","short":"G.H. Choueiri, J.M. Lopez Alonso, B. Hof, Physical Review Letters 120 (2018).","apa":"Choueiri, G. H., Lopez Alonso, J. M., & Hof, B. (2018). Exceeding the asymptotic limit of polymer drag reduction. Physical Review Letters. American Physical Society. https://doi.org/10.1103/PhysRevLett.120.124501","ama":"Choueiri GH, Lopez Alonso JM, Hof B. Exceeding the asymptotic limit of polymer drag reduction. Physical Review Letters. 2018;120(12). doi:10.1103/PhysRevLett.120.124501","mla":"Choueiri, George H., et al. “Exceeding the Asymptotic Limit of Polymer Drag Reduction.” Physical Review Letters, vol. 120, no. 12, 124501, American Physical Society, 2018, doi:10.1103/PhysRevLett.120.124501.","ista":"Choueiri GH, Lopez Alonso JM, Hof B. 2018. Exceeding the asymptotic limit of polymer drag reduction. Physical Review Letters. 120(12), 124501.","chicago":"Choueiri, George H, Jose M Lopez Alonso, and Björn Hof. “Exceeding the Asymptotic Limit of Polymer Drag Reduction.” Physical Review Letters. American Physical Society, 2018. https://doi.org/10.1103/PhysRevLett.120.124501."},"project":[{"call_identifier":"FP7","_id":"25681D80-B435-11E9-9278-68D0E5697425","grant_number":"291734","name":"International IST Postdoc Fellowship Programme"},{"name":"Decoding the complexity of turbulence at its origin","grant_number":"306589","call_identifier":"FP7","_id":"25152F3A-B435-11E9-9278-68D0E5697425"}],"article_number":"124501","ec_funded":1,"issue":"12","volume":120,"language":[{"iso":"eng"}],"publication_status":"published","intvolume":" 120","month":"03","main_file_link":[{"url":"https://arxiv.org/abs/1703.06271","open_access":"1"}],"scopus_import":"1","oa_version":"Preprint","acknowledged_ssus":[{"_id":"SSU"}],"abstract":[{"text":"The drag of turbulent flows can be drastically decreased by adding small amounts of high molecular weight polymers. While drag reduction initially increases with polymer concentration, it eventually saturates to what is known as the maximum drag reduction (MDR) asymptote; this asymptote is generally attributed to the dynamics being reduced to a marginal yet persistent state of subdued turbulent motion. Contrary to this accepted view, we show that, for an appropriate choice of parameters, polymers can reduce the drag beyond the suggested asymptotic limit, eliminating turbulence and giving way to laminar flow. At higher polymer concentrations, however, the laminar state becomes unstable, resulting in a fluctuating flow with the characteristic drag of the MDR asymptote. Our findings indicate that the asymptotic state is hence dynamically disconnected from ordinary turbulence. © 2018 American Physical Society.","lang":"eng"}],"department":[{"_id":"BjHo"}],"date_updated":"2023-10-10T13:27:44Z","status":"public","type":"journal_article","_id":"328"},{"issue":"2","volume":98,"publication_status":"published","language":[{"iso":"eng"}],"main_file_link":[{"url":"https://arxiv.org/abs/1808.02088","open_access":"1"}],"scopus_import":"1","intvolume":" 98","month":"08","abstract":[{"lang":"eng","text":"Recent studies suggest that unstable, nonchaotic solutions of the Navier-Stokes equation may provide deep insights into fluid turbulence. In this article, we present a combined experimental and numerical study exploring the dynamical role of unstable equilibrium solutions and their invariant manifolds in a weakly turbulent, electromagnetically driven, shallow fluid layer. Identifying instants when turbulent evolution slows down, we compute 31 unstable equilibria of a realistic two-dimensional model of the flow. We establish the dynamical relevance of these unstable equilibria by showing that they are closely visited by the turbulent flow. We also establish the dynamical relevance of unstable manifolds by verifying that they are shadowed by turbulent trajectories departing from the neighborhoods of unstable equilibria over large distances in state space."}],"oa_version":"Submitted Version","department":[{"_id":"BjHo"}],"date_updated":"2023-10-10T13:29:10Z","type":"journal_article","status":"public","_id":"136","date_created":"2018-12-11T11:44:49Z","date_published":"2018-08-13T00:00:00Z","doi":"10.1103/PhysRevE.98.023105","year":"2018","isi":1,"publication":"Physical Review E","day":"13","oa":1,"quality_controlled":"1","publisher":"American Physical Society","article_processing_charge":"No","external_id":{"arxiv":["1808.02088"],"isi":["000441466800010"]},"author":[{"full_name":"Suri, Balachandra","last_name":"Suri","id":"47A5E706-F248-11E8-B48F-1D18A9856A87","first_name":"Balachandra"},{"first_name":"Jeffrey","last_name":"Tithof","full_name":"Tithof, Jeffrey"},{"full_name":"Grigoriev, Roman","last_name":"Grigoriev","first_name":"Roman"},{"first_name":"Michael","full_name":"Schatz, Michael","last_name":"Schatz"}],"title":"Unstable equilibria and invariant manifolds in quasi-two-dimensional Kolmogorov-like flow","citation":{"short":"B. Suri, J. Tithof, R. Grigoriev, M. Schatz, Physical Review E 98 (2018).","ieee":"B. Suri, J. Tithof, R. Grigoriev, and M. Schatz, “Unstable equilibria and invariant manifolds in quasi-two-dimensional Kolmogorov-like flow,” Physical Review E, vol. 98, no. 2. American Physical Society, 2018.","ama":"Suri B, Tithof J, Grigoriev R, Schatz M. Unstable equilibria and invariant manifolds in quasi-two-dimensional Kolmogorov-like flow. Physical Review E. 2018;98(2). doi:10.1103/PhysRevE.98.023105","apa":"Suri, B., Tithof, J., Grigoriev, R., & Schatz, M. (2018). Unstable equilibria and invariant manifolds in quasi-two-dimensional Kolmogorov-like flow. Physical Review E. American Physical Society. https://doi.org/10.1103/PhysRevE.98.023105","mla":"Suri, Balachandra, et al. “Unstable Equilibria and Invariant Manifolds in Quasi-Two-Dimensional Kolmogorov-like Flow.” Physical Review E, vol. 98, no. 2, American Physical Society, 2018, doi:10.1103/PhysRevE.98.023105.","ista":"Suri B, Tithof J, Grigoriev R, Schatz M. 2018. Unstable equilibria and invariant manifolds in quasi-two-dimensional Kolmogorov-like flow. Physical Review E. 98(2).","chicago":"Suri, Balachandra, Jeffrey Tithof, Roman Grigoriev, and Michael Schatz. “Unstable Equilibria and Invariant Manifolds in Quasi-Two-Dimensional Kolmogorov-like Flow.” Physical Review E. American Physical Society, 2018. https://doi.org/10.1103/PhysRevE.98.023105."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87"},{"page":"919 - 942","date_created":"2018-12-11T11:46:23Z","date_published":"2018-01-01T00:00:00Z","doi":"10.1007/s10494-018-9896-4","year":"2018","isi":1,"has_accepted_license":"1","publication":"Flow Turbulence and Combustion","day":"01","oa":1,"quality_controlled":"1","publisher":"Springer","article_processing_charge":"Yes (via OA deal)","external_id":{"isi":["000433113900004"]},"publist_id":"7401","author":[{"first_name":"Jakob","id":"3A47AE32-F248-11E8-B48F-1D18A9856A87","full_name":"Kühnen, Jakob","orcid":"0000-0003-4312-0179","last_name":"Kühnen"},{"last_name":"Scarselli","orcid":"0000-0001-5227-4271","full_name":"Scarselli, Davide","id":"40315C30-F248-11E8-B48F-1D18A9856A87","first_name":"Davide"},{"last_name":"Schaner","full_name":"Schaner, Markus","id":"316CE034-F248-11E8-B48F-1D18A9856A87","first_name":"Markus"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754"}],"title":"Relaminarization by steady modification of the streamwise velocity profile in a pipe","citation":{"chicago":"Kühnen, Jakob, Davide Scarselli, Markus Schaner, and Björn Hof. “Relaminarization by Steady Modification of the Streamwise Velocity Profile in a Pipe.” Flow Turbulence and Combustion. Springer, 2018. https://doi.org/10.1007/s10494-018-9896-4.","ista":"Kühnen J, Scarselli D, Schaner M, Hof B. 2018. Relaminarization by steady modification of the streamwise velocity profile in a pipe. Flow Turbulence and Combustion. 100(4), 919–942.","mla":"Kühnen, Jakob, et al. “Relaminarization by Steady Modification of the Streamwise Velocity Profile in a Pipe.” Flow Turbulence and Combustion, vol. 100, no. 4, Springer, 2018, pp. 919–42, doi:10.1007/s10494-018-9896-4.","apa":"Kühnen, J., Scarselli, D., Schaner, M., & Hof, B. (2018). Relaminarization by steady modification of the streamwise velocity profile in a pipe. Flow Turbulence and Combustion. Springer. https://doi.org/10.1007/s10494-018-9896-4","ama":"Kühnen J, Scarselli D, Schaner M, Hof B. Relaminarization by steady modification of the streamwise velocity profile in a pipe. Flow Turbulence and Combustion. 2018;100(4):919-942. doi:10.1007/s10494-018-9896-4","short":"J. Kühnen, D. Scarselli, M. Schaner, B. Hof, Flow Turbulence and Combustion 100 (2018) 919–942.","ieee":"J. Kühnen, D. Scarselli, M. Schaner, and B. Hof, “Relaminarization by steady modification of the streamwise velocity profile in a pipe,” Flow Turbulence and Combustion, vol. 100, no. 4. Springer, pp. 919–942, 2018."},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","project":[{"_id":"25152F3A-B435-11E9-9278-68D0E5697425","call_identifier":"FP7","grant_number":"306589","name":"Decoding the complexity of turbulence at its origin"}],"ec_funded":1,"volume":100,"issue":"4","related_material":{"record":[{"relation":"dissertation_contains","id":"7258","status":"public"}]},"publication_status":"published","language":[{"iso":"eng"}],"file":[{"date_updated":"2020-07-14T12:46:25Z","file_size":2210020,"creator":"dernst","date_created":"2018-12-17T15:52:37Z","file_name":"2018_FlowTurbulenceCombust_Kuehnen.pdf","content_type":"application/pdf","access_level":"open_access","relation":"main_file","checksum":"d7c0bade150faabca150b0a9986e60ca","file_id":"5717"}],"scopus_import":"1","intvolume":" 100","month":"01","abstract":[{"lang":"eng","text":"We show that a rather simple, steady modification of the streamwise velocity profile in a pipe can lead to a complete collapse of turbulence and the flow fully relaminarizes. Two different devices, a stationary obstacle (inset) and a device which injects fluid through an annular gap close to the wall, are used to control the flow. Both devices modify the streamwise velocity profile such that the flow in the center of the pipe is decelerated and the flow in the near wall region is accelerated. We present measurements with stereoscopic particle image velocimetry to investigate and capture the development of the relaminarizing flow downstream these devices and the specific circumstances responsible for relaminarization. We find total relaminarization up to Reynolds numbers of 6000, where the skin friction in the far downstream distance is reduced by a factor of 3.4 due to relaminarization. In a smooth straight pipe the flow remains completely laminar downstream of the control. Furthermore, we show that transient (temporary) relaminarization in a spatially confined region right downstream the devices occurs also at much higher Reynolds numbers, accompanied by a significant local skin friction drag reduction. The underlying physical mechanism of relaminarization is attributed to a weakening of the near-wall turbulence production cycle."}],"oa_version":"Published Version","file_date_updated":"2020-07-14T12:46:25Z","department":[{"_id":"BjHo"}],"date_updated":"2024-03-27T23:30:36Z","ddc":["530"],"tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"type":"journal_article","status":"public","_id":"422"},{"_id":"461","status":"public","type":"journal_article","date_updated":"2024-03-27T23:30:36Z","department":[{"_id":"BjHo"}],"oa_version":"Preprint","abstract":[{"lang":"eng","text":"Turbulence is the major cause of friction losses in transport processes and it is responsible for a drastic drag increase in flows over bounding surfaces. While much effort is invested into developing ways to control and reduce turbulence intensities, so far no methods exist to altogether eliminate turbulence if velocities are sufficiently large. We demonstrate for pipe flow that appropriate distortions to the velocity profile lead to a complete collapse of turbulence and subsequently friction losses are reduced by as much as 90%. Counterintuitively, the return to laminar motion is accomplished by initially increasing turbulence intensities or by transiently amplifying wall shear. Since neither the Reynolds number nor the shear stresses decrease (the latter often increase), these measures are not indicative of turbulence collapse. Instead, an amplification mechanism measuring the interaction between eddies and the mean shear is found to set a threshold below which turbulence is suppressed beyond recovery."}],"month":"01","intvolume":" 14","scopus_import":"1","main_file_link":[{"url":"https://arxiv.org/abs/1711.06543","open_access":"1"}],"language":[{"iso":"eng"}],"publication_status":"published","related_material":{"record":[{"id":"12726","status":"public","relation":"dissertation_contains"},{"relation":"dissertation_contains","id":"14530","status":"public"},{"relation":"dissertation_contains","id":"7258","status":"public"}]},"volume":14,"ec_funded":1,"project":[{"grant_number":"306589","name":"Decoding the complexity of turbulence at its origin","_id":"25152F3A-B435-11E9-9278-68D0E5697425","call_identifier":"FP7"},{"name":"Eliminating turbulence in oil pipelines","grant_number":"737549","_id":"25104D44-B435-11E9-9278-68D0E5697425","call_identifier":"H2020"}],"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"mla":"Kühnen, Jakob, et al. “Destabilizing Turbulence in Pipe Flow.” Nature Physics, vol. 14, Nature Publishing Group, 2018, pp. 386–90, doi:10.1038/s41567-017-0018-3.","short":"J. Kühnen, B. Song, D. Scarselli, N.B. Budanur, M. Riedl, A. Willis, M. Avila, B. Hof, Nature Physics 14 (2018) 386–390.","ieee":"J. Kühnen et al., “Destabilizing turbulence in pipe flow,” Nature Physics, vol. 14. Nature Publishing Group, pp. 386–390, 2018.","apa":"Kühnen, J., Song, B., Scarselli, D., Budanur, N. B., Riedl, M., Willis, A., … Hof, B. (2018). Destabilizing turbulence in pipe flow. Nature Physics. Nature Publishing Group. https://doi.org/10.1038/s41567-017-0018-3","ama":"Kühnen J, Song B, Scarselli D, et al. Destabilizing turbulence in pipe flow. Nature Physics. 2018;14:386-390. doi:10.1038/s41567-017-0018-3","chicago":"Kühnen, Jakob, Baofang Song, Davide Scarselli, Nazmi B Budanur, Michael Riedl, Ashley Willis, Marc Avila, and Björn Hof. “Destabilizing Turbulence in Pipe Flow.” Nature Physics. Nature Publishing Group, 2018. https://doi.org/10.1038/s41567-017-0018-3.","ista":"Kühnen J, Song B, Scarselli D, Budanur NB, Riedl M, Willis A, Avila M, Hof B. 2018. Destabilizing turbulence in pipe flow. Nature Physics. 14, 386–390."},"title":"Destabilizing turbulence in pipe flow","publist_id":"7360","author":[{"last_name":"Kühnen","orcid":"0000-0003-4312-0179","full_name":"Kühnen, Jakob","id":"3A47AE32-F248-11E8-B48F-1D18A9856A87","first_name":"Jakob"},{"full_name":"Song, Baofang","last_name":"Song","first_name":"Baofang"},{"orcid":"0000-0001-5227-4271","full_name":"Scarselli, Davide","last_name":"Scarselli","id":"40315C30-F248-11E8-B48F-1D18A9856A87","first_name":"Davide"},{"id":"3EA1010E-F248-11E8-B48F-1D18A9856A87","first_name":"Nazmi B","full_name":"Budanur, Nazmi B","orcid":"0000-0003-0423-5010","last_name":"Budanur"},{"id":"3BE60946-F248-11E8-B48F-1D18A9856A87","first_name":"Michael","last_name":"Riedl","orcid":"0000-0003-4844-6311","full_name":"Riedl, Michael"},{"first_name":"Ashley","last_name":"Willis","full_name":"Willis, Ashley"},{"last_name":"Avila","full_name":"Avila, Marc","first_name":"Marc"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","last_name":"Hof","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn"}],"external_id":{"isi":["000429434100020"]},"article_processing_charge":"No","acknowledgement":"We acknowledge the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement 306589, the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 737549) and the Deutsche Forschungsgemeinschaft (Project No. FOR 1182) for financial support. We thank our technician P. Maier for providing highly valuable ideas and greatly supporting us in all technical aspects. We thank M. Schaner for technical drawings, construction and design. We thank M. Schwegel for a Matlab code to post-process experimental data.","publisher":"Nature Publishing Group","quality_controlled":"1","oa":1,"day":"08","publication":"Nature Physics","isi":1,"year":"2018","date_published":"2018-01-08T00:00:00Z","doi":"10.1038/s41567-017-0018-3","date_created":"2018-12-11T11:46:36Z","page":"386-390"},{"user_id":"3E5EF7F0-F248-11E8-B48F-1D18A9856A87","citation":{"ama":"Budanur NB, Cvitanović P. Unstable manifolds of relative periodic orbits in the symmetry reduced state space of the Kuramoto–Sivashinsky system. Journal of Statistical Physics. 2017;167(3-4):636-655. doi:10.1007/s10955-016-1672-z","apa":"Budanur, N. B., & Cvitanović, P. (2017). Unstable manifolds of relative periodic orbits in the symmetry reduced state space of the Kuramoto–Sivashinsky system. Journal of Statistical Physics. Springer. https://doi.org/10.1007/s10955-016-1672-z","ieee":"N. B. Budanur and P. Cvitanović, “Unstable manifolds of relative periodic orbits in the symmetry reduced state space of the Kuramoto–Sivashinsky system,” Journal of Statistical Physics, vol. 167, no. 3–4. Springer, pp. 636–655, 2017.","short":"N.B. Budanur, P. Cvitanović, Journal of Statistical Physics 167 (2017) 636–655.","mla":"Budanur, Nazmi B., and Predrag Cvitanović. “Unstable Manifolds of Relative Periodic Orbits in the Symmetry Reduced State Space of the Kuramoto–Sivashinsky System.” Journal of Statistical Physics, vol. 167, no. 3–4, Springer, 2017, pp. 636–55, doi:10.1007/s10955-016-1672-z.","ista":"Budanur NB, Cvitanović P. 2017. Unstable manifolds of relative periodic orbits in the symmetry reduced state space of the Kuramoto–Sivashinsky system. Journal of Statistical Physics. 167(3–4), 636–655.","chicago":"Budanur, Nazmi B, and Predrag Cvitanović. “Unstable Manifolds of Relative Periodic Orbits in the Symmetry Reduced State Space of the Kuramoto–Sivashinsky System.” Journal of Statistical Physics. Springer, 2017. https://doi.org/10.1007/s10955-016-1672-z."},"title":"Unstable manifolds of relative periodic orbits in the symmetry reduced state space of the Kuramoto–Sivashinsky system","publist_id":"6136","author":[{"last_name":"Budanur","full_name":"Budanur, Nazmi B","orcid":"0000-0003-0423-5010","id":"3EA1010E-F248-11E8-B48F-1D18A9856A87","first_name":"Nazmi B"},{"first_name":"Predrag","last_name":"Cvitanović","full_name":"Cvitanović, Predrag"}],"acknowledgement":"This work was supported by the family of late G. Robinson, Jr. and NSF Grant DMS-1211827. ","oa":1,"quality_controlled":"1","publisher":"Springer","publication":"Journal of Statistical Physics","day":"01","year":"2017","has_accepted_license":"1","date_created":"2018-12-11T11:50:44Z","doi":"10.1007/s10955-016-1672-z","date_published":"2017-05-01T00:00:00Z","page":"636-655","_id":"1211","pubrep_id":"782","status":"public","type":"journal_article","ddc":["530"],"date_updated":"2021-01-12T06:49:07Z","file_date_updated":"2020-07-14T12:44:39Z","department":[{"_id":"BjHo"}],"oa_version":"Submitted Version","abstract":[{"lang":"eng","text":"Systems such as fluid flows in channels and pipes or the complex Ginzburg–Landau system, defined over periodic domains, exhibit both continuous symmetries, translational and rotational, as well as discrete symmetries under spatial reflections or complex conjugation. The simplest, and very common symmetry of this type is the equivariance of the defining equations under the orthogonal group O(2). We formulate a novel symmetry reduction scheme for such systems by combining the method of slices with invariant polynomial methods, and show how it works by applying it to the Kuramoto–Sivashinsky system in one spatial dimension. As an example, we track a relative periodic orbit through a sequence of bifurcations to the onset of chaos. Within the symmetry-reduced state space we are able to compute and visualize the unstable manifolds of relative periodic orbits, their torus bifurcations, a transition to chaos via torus breakdown, and heteroclinic connections between various relative periodic orbits. It would be very hard to carry through such analysis in the full state space, without a symmetry reduction such as the one we present here."}],"intvolume":" 167","month":"05","scopus_import":1,"language":[{"iso":"eng"}],"file":[{"creator":"system","file_size":2820207,"date_updated":"2020-07-14T12:44:39Z","file_name":"IST-2017-782-v1+1_BudCvi15.pdf","date_created":"2018-12-12T10:18:01Z","relation":"main_file","access_level":"open_access","content_type":"application/pdf","file_id":"5319","checksum":"3e971d09eb167761aa0888ed415b0056"}],"publication_status":"published","volume":167,"issue":"3-4"},{"day":"01","publication":"Physical Review Fluids","language":[{"iso":"eng"}],"year":"2017","publication_status":"published","date_published":"2017-04-01T00:00:00Z","issue":"4","volume":2,"doi":"10.1103/PhysRevFluids.2.043904","date_created":"2018-12-11T11:46:54Z","oa_version":"Preprint","abstract":[{"lang":"eng","text":"We present an experimental setup that creates a shear flow with zero mean advection velocity achieved by counterbalancing the nonzero streamwise pressure gradient by moving boundaries, which generates plane Couette-Poiseuille flow. We obtain experimental results in the transitional regime for this flow. Using flow visualization, we characterize the subcritical transition to turbulence in Couette-Poiseuille flow and show the existence of turbulent spots generated by a permanent perturbation. Due to the zero mean advection velocity of the base profile, these turbulent structures are nearly stationary. We distinguish two regions of the turbulent spot: the active turbulent core, which is characterized by waviness of the streaks similar to traveling waves, and the surrounding region, which includes in addition the weak undisturbed streaks and oblique waves at the laminar-turbulent interface. We also study the dependence of the size of these two regions on Reynolds number. Finally, we show that the traveling waves move in the downstream (Poiseuille) direction."}],"month":"04","intvolume":" 2","quality_controlled":"1","scopus_import":1,"publisher":"American Physical Society","main_file_link":[{"url":"https://arxiv.org/abs/1704.02619","open_access":"1"}],"oa":1,"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"ieee":"L. Klotz, G. M. Lemoult, I. Frontczak, L. Tuckerman, and J. Wesfreid, “Couette-Poiseuille flow experiment with zero mean advection velocity: Subcritical transition to turbulence,” Physical Review Fluids, vol. 2, no. 4. American Physical Society, 2017.","short":"L. Klotz, G.M. Lemoult, I. Frontczak, L. Tuckerman, J. Wesfreid, Physical Review Fluids 2 (2017).","apa":"Klotz, L., Lemoult, G. M., Frontczak, I., Tuckerman, L., & Wesfreid, J. (2017). Couette-Poiseuille flow experiment with zero mean advection velocity: Subcritical transition to turbulence. Physical Review Fluids. American Physical Society. https://doi.org/10.1103/PhysRevFluids.2.043904","ama":"Klotz L, Lemoult GM, Frontczak I, Tuckerman L, Wesfreid J. Couette-Poiseuille flow experiment with zero mean advection velocity: Subcritical transition to turbulence. Physical Review Fluids. 2017;2(4). doi:10.1103/PhysRevFluids.2.043904","mla":"Klotz, Lukasz, et al. “Couette-Poiseuille Flow Experiment with Zero Mean Advection Velocity: Subcritical Transition to Turbulence.” Physical Review Fluids, vol. 2, no. 4, 043904, American Physical Society, 2017, doi:10.1103/PhysRevFluids.2.043904.","ista":"Klotz L, Lemoult GM, Frontczak I, Tuckerman L, Wesfreid J. 2017. Couette-Poiseuille flow experiment with zero mean advection velocity: Subcritical transition to turbulence. Physical Review Fluids. 2(4), 043904.","chicago":"Klotz, Lukasz, Grégoire M Lemoult, Idalia Frontczak, Laurette Tuckerman, and José Wesfreid. “Couette-Poiseuille Flow Experiment with Zero Mean Advection Velocity: Subcritical Transition to Turbulence.” Physical Review Fluids. American Physical Society, 2017. https://doi.org/10.1103/PhysRevFluids.2.043904."},"date_updated":"2021-01-12T08:01:16Z","department":[{"_id":"BjHo"}],"title":"Couette-Poiseuille flow experiment with zero mean advection velocity: Subcritical transition to turbulence","publist_id":"7306","author":[{"first_name":"Lukasz","id":"2C9AF1C2-F248-11E8-B48F-1D18A9856A87","last_name":"Klotz","orcid":"0000-0003-1740-7635","full_name":"Klotz, Lukasz"},{"id":"4787FE80-F248-11E8-B48F-1D18A9856A87","first_name":"Grégoire M","last_name":"Lemoult","full_name":"Lemoult, Grégoire M"},{"first_name":"Idalia","full_name":"Frontczak, Idalia","last_name":"Frontczak"},{"first_name":"Laurette","full_name":"Tuckerman, Laurette","last_name":"Tuckerman"},{"first_name":"José","last_name":"Wesfreid","full_name":"Wesfreid, José"}],"article_number":"043904","_id":"513","status":"public","type":"journal_article"},{"type":"journal_article","status":"public","_id":"651","publist_id":"7116","author":[{"last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87"}],"department":[{"_id":"BjHo"}],"title":"Fluid dynamics: Water flows out of touch","citation":{"ista":"Hof B. 2017. Fluid dynamics: Water flows out of touch. Nature. 541(7636), 161–162.","chicago":"Hof, Björn. “Fluid Dynamics: Water Flows out of Touch.” Nature. Nature Publishing Group, 2017. https://doi.org/10.1038/541161a.","apa":"Hof, B. (2017). Fluid dynamics: Water flows out of touch. Nature. Nature Publishing Group. https://doi.org/10.1038/541161a","ama":"Hof B. Fluid dynamics: Water flows out of touch. Nature. 2017;541(7636):161-162. doi:10.1038/541161a","ieee":"B. Hof, “Fluid dynamics: Water flows out of touch,” Nature, vol. 541, no. 7636. Nature Publishing Group, pp. 161–162, 2017.","short":"B. Hof, Nature 541 (2017) 161–162.","mla":"Hof, Björn. “Fluid Dynamics: Water Flows out of Touch.” Nature, vol. 541, no. 7636, Nature Publishing Group, 2017, pp. 161–62, doi:10.1038/541161a."},"date_updated":"2021-01-12T08:07:49Z","user_id":"4435EBFC-F248-11E8-B48F-1D18A9856A87","publisher":"Nature Publishing Group","scopus_import":1,"quality_controlled":"1","intvolume":" 541","month":"01","abstract":[{"text":"Superhydrophobic surfaces reduce the frictional drag between water and solid materials, but this effect is often temporary. The realization of sustained drag reduction has applications for water vehicles and pipeline flows.\r\n\r\n","lang":"eng"}],"oa_version":"None","page":"161 - 162","date_created":"2018-12-11T11:47:43Z","doi":"10.1038/541161a","volume":541,"issue":"7636","date_published":"2017-01-11T00:00:00Z","year":"2017","publication_status":"published","publication_identifier":{"issn":["00280836"]},"publication":"Nature","language":[{"iso":"eng"}],"day":"11"},{"project":[{"_id":"2511D90C-B435-11E9-9278-68D0E5697425","grant_number":"SFB 963 TP A8","name":"Astrophysical instability of currents and turbulences"}],"article_number":"044107","title":"Hydrodynamic turbulence in quasi Keplerian rotating flows","publist_id":"7072","author":[{"full_name":"Shi, Liang","last_name":"Shi","first_name":"Liang"},{"full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof","id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn"},{"full_name":"Rampp, Markus","last_name":"Rampp","first_name":"Markus"},{"last_name":"Avila","full_name":"Avila, Marc","first_name":"Marc"}],"user_id":"4435EBFC-F248-11E8-B48F-1D18A9856A87","citation":{"mla":"Shi, Liang, et al. “Hydrodynamic Turbulence in Quasi Keplerian Rotating Flows.” Physics of Fluids, vol. 29, no. 4, 044107, American Institute of Physics, 2017, doi:10.1063/1.4981525.","apa":"Shi, L., Hof, B., Rampp, M., & Avila, M. (2017). Hydrodynamic turbulence in quasi Keplerian rotating flows. Physics of Fluids. American Institute of Physics. https://doi.org/10.1063/1.4981525","ama":"Shi L, Hof B, Rampp M, Avila M. Hydrodynamic turbulence in quasi Keplerian rotating flows. Physics of Fluids. 2017;29(4). doi:10.1063/1.4981525","ieee":"L. Shi, B. Hof, M. Rampp, and M. Avila, “Hydrodynamic turbulence in quasi Keplerian rotating flows,” Physics of Fluids, vol. 29, no. 4. American Institute of Physics, 2017.","short":"L. Shi, B. Hof, M. Rampp, M. Avila, Physics of Fluids 29 (2017).","chicago":"Shi, Liang, Björn Hof, Markus Rampp, and Marc Avila. “Hydrodynamic Turbulence in Quasi Keplerian Rotating Flows.” Physics of Fluids. American Institute of Physics, 2017. https://doi.org/10.1063/1.4981525.","ista":"Shi L, Hof B, Rampp M, Avila M. 2017. Hydrodynamic turbulence in quasi Keplerian rotating flows. Physics of Fluids. 29(4), 044107."},"oa":1,"publisher":"American Institute of Physics","quality_controlled":"1","date_created":"2018-12-11T11:47:47Z","doi":"10.1063/1.4981525","date_published":"2017-04-01T00:00:00Z","publication":"Physics of Fluids","day":"01","year":"2017","status":"public","type":"journal_article","_id":"662","department":[{"_id":"BjHo"}],"date_updated":"2021-01-12T08:08:15Z","intvolume":" 29","month":"04","main_file_link":[{"url":"https://arxiv.org/abs/1703.01714","open_access":"1"}],"scopus_import":1,"oa_version":"Submitted Version","abstract":[{"lang":"eng","text":"We report a direct-numerical-simulation study of the Taylor-Couette flow in the quasi-Keplerian regime at shear Reynolds numbers up to (105). Quasi-Keplerian rotating flow has been investigated for decades as a simplified model system to study the origin of turbulence in accretion disks that is not fully understood. The flow in this study is axially periodic and thus the experimental end-wall effects on the stability of the flow are avoided. Using optimal linear perturbations as initial conditions, our simulations find no sustained turbulence: the strong initial perturbations distort the velocity profile and trigger turbulence that eventually decays."}],"issue":"4","volume":29,"language":[{"iso":"eng"}],"publication_status":"published","publication_identifier":{"issn":["10706631"]}},{"_id":"1160","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"type":"journal_article","pubrep_id":"743","status":"public","date_updated":"2023-09-20T11:28:49Z","ddc":["532"],"department":[{"_id":"BjHo"}],"file_date_updated":"2020-07-14T12:44:36Z","abstract":[{"lang":"eng","text":"We investigate fundamental nonlinear dynamics of ferrofluidic Taylor-Couette flow - flow confined be-tween two concentric independently rotating cylinders - consider small aspect ratio by solving the ferro-hydrodynamical equations, carrying out systematic bifurcation analysis. Without magnetic field, we find steady flow patterns, previously observed with a simple fluid, such as those containing normal one- or two vortex cells, as well as anomalous one-cell and twin-cell flow states. However, when a symmetry-breaking transverse magnetic field is present, all flow states exhibit stimulated, finite two-fold mode. Various bifurcations between steady and unsteady states can occur, corresponding to the transitions between the two-cell and one-cell states. While unsteady, axially oscillating flow states can arise, we also detect the emergence of new unsteady flow states. In particular, we uncover two new states: one contains only the azimuthally oscillating solution in the configuration of the twin-cell flow state, and an-other a rotating flow state. Topologically, these flow states are a limit cycle and a quasiperiodic solution on a two-torus, respectively. Emergence of new flow states in addition to observed ones with classical fluid, indicates that richer but potentially more controllable dynamics in ferrofluidic flows, as such flow states depend on the external magnetic field."}],"oa_version":"Published Version","scopus_import":"1","intvolume":" 7","month":"01","publication_status":"published","publication_identifier":{"issn":["20452322"]},"language":[{"iso":"eng"}],"file":[{"creator":"system","file_size":4546835,"date_updated":"2020-07-14T12:44:36Z","file_name":"IST-2017-743-v1+1_srep40012.pdf","date_created":"2018-12-12T10:10:16Z","relation":"main_file","access_level":"open_access","content_type":"application/pdf","checksum":"694aa70399444570825099c1a7ec91f2","file_id":"4802"}],"volume":7,"article_number":"40012","citation":{"ieee":"S. Altmeyer, Y. Do, and Y. Lai, “Dynamics of ferrofluidic flow in the Taylor-Couette system with a small aspect ratio,” Scientific Reports, vol. 7. Nature Publishing Group, 2017.","short":"S. Altmeyer, Y. Do, Y. Lai, Scientific Reports 7 (2017).","apa":"Altmeyer, S., Do, Y., & Lai, Y. (2017). Dynamics of ferrofluidic flow in the Taylor-Couette system with a small aspect ratio. Scientific Reports. Nature Publishing Group. https://doi.org/10.1038/srep40012","ama":"Altmeyer S, Do Y, Lai Y. Dynamics of ferrofluidic flow in the Taylor-Couette system with a small aspect ratio. Scientific Reports. 2017;7. doi:10.1038/srep40012","mla":"Altmeyer, Sebastian, et al. “Dynamics of Ferrofluidic Flow in the Taylor-Couette System with a Small Aspect Ratio.” Scientific Reports, vol. 7, 40012, Nature Publishing Group, 2017, doi:10.1038/srep40012.","ista":"Altmeyer S, Do Y, Lai Y. 2017. Dynamics of ferrofluidic flow in the Taylor-Couette system with a small aspect ratio. Scientific Reports. 7, 40012.","chicago":"Altmeyer, Sebastian, Younghae Do, and Ying Lai. “Dynamics of Ferrofluidic Flow in the Taylor-Couette System with a Small Aspect Ratio.” Scientific Reports. Nature Publishing Group, 2017. https://doi.org/10.1038/srep40012."},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","article_processing_charge":"No","external_id":{"isi":["000391269700001"]},"author":[{"id":"2EE67FDC-F248-11E8-B48F-1D18A9856A87","first_name":"Sebastian","orcid":"0000-0001-5964-0203","full_name":"Altmeyer, Sebastian","last_name":"Altmeyer"},{"first_name":"Younghae","full_name":"Do, Younghae","last_name":"Do"},{"full_name":"Lai, Ying","last_name":"Lai","first_name":"Ying"}],"publist_id":"6198","title":"Dynamics of ferrofluidic flow in the Taylor-Couette system with a small aspect ratio","oa":1,"publisher":"Nature Publishing Group","quality_controlled":"1","year":"2017","isi":1,"has_accepted_license":"1","publication":"Scientific Reports","day":"06","date_created":"2018-12-11T11:50:28Z","doi":"10.1038/srep40012","date_published":"2017-01-06T00:00:00Z"},{"quality_controlled":"1","publisher":"Cambridge University Press","oa":1,"date_published":"2017-02-25T00:00:00Z","doi":"10.1017/jfm.2017.14","date_created":"2018-12-11T11:50:04Z","page":"1045 - 1059","day":"25","publication":"Journal of Fluid Mechanics","isi":1,"year":"2017","project":[{"call_identifier":"FP7","_id":"25152F3A-B435-11E9-9278-68D0E5697425","grant_number":"306589","name":"Decoding the complexity of turbulence at its origin"}],"title":"Speed and structure of turbulent fronts in pipe flow","publist_id":"6290","author":[{"first_name":"Baofang","last_name":"Song","full_name":"Song, Baofang"},{"first_name":"Dwight","last_name":"Barkley","full_name":"Barkley, Dwight"},{"orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof","first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Avila","full_name":"Avila, Marc","first_name":"Marc"}],"external_id":{"isi":["000394376400044"]},"article_processing_charge":"No","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"ista":"Song B, Barkley D, Hof B, Avila M. 2017. Speed and structure of turbulent fronts in pipe flow. Journal of Fluid Mechanics. 813, 1045–1059.","chicago":"Song, Baofang, Dwight Barkley, Björn Hof, and Marc Avila. “Speed and Structure of Turbulent Fronts in Pipe Flow.” Journal of Fluid Mechanics. Cambridge University Press, 2017. https://doi.org/10.1017/jfm.2017.14.","apa":"Song, B., Barkley, D., Hof, B., & Avila, M. (2017). Speed and structure of turbulent fronts in pipe flow. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2017.14","ama":"Song B, Barkley D, Hof B, Avila M. Speed and structure of turbulent fronts in pipe flow. Journal of Fluid Mechanics. 2017;813:1045-1059. doi:10.1017/jfm.2017.14","short":"B. Song, D. Barkley, B. Hof, M. Avila, Journal of Fluid Mechanics 813 (2017) 1045–1059.","ieee":"B. Song, D. Barkley, B. Hof, and M. Avila, “Speed and structure of turbulent fronts in pipe flow,” Journal of Fluid Mechanics, vol. 813. Cambridge University Press, pp. 1045–1059, 2017.","mla":"Song, Baofang, et al. “Speed and Structure of Turbulent Fronts in Pipe Flow.” Journal of Fluid Mechanics, vol. 813, Cambridge University Press, 2017, pp. 1045–59, doi:10.1017/jfm.2017.14."},"month":"02","intvolume":" 813","scopus_import":"1","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1603.04077"}],"oa_version":"Submitted Version","abstract":[{"text":"Using extensive direct numerical simulations, the dynamics of laminar-turbulent fronts in pipe flow is investigated for Reynolds numbers between and 5500. We here investigate the physical distinction between the fronts of weak and strong slugs both by analysing the turbulent kinetic energy budget and by comparing the downstream front motion to the advection speed of bulk turbulent structures. Our study shows that weak downstream fronts travel slower than turbulent structures in the bulk and correspond to decaying turbulence at the front. At the downstream front speed becomes faster than the advection speed, marking the onset of strong fronts. In contrast to weak fronts, turbulent eddies are generated at strong fronts by feeding on the downstream laminar flow. Our study also suggests that temporal fluctuations of production and dissipation at the downstream laminar-turbulent front drive the dynamical switches between the two types of front observed up to.","lang":"eng"}],"acknowledged_ssus":[{"_id":"ScienComp"}],"volume":813,"ec_funded":1,"language":[{"iso":"eng"}],"publication_identifier":{"issn":["00221120"]},"publication_status":"published","status":"public","type":"journal_article","_id":"1087","department":[{"_id":"BjHo"}],"date_updated":"2023-09-20T11:47:22Z"},{"project":[{"_id":"255008E4-B435-11E9-9278-68D0E5697425","name":"Information processing and computation in fish groups","grant_number":"RGP0065/2012"}],"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"mla":"Lopez Alonso, Jose M., and Marc Avila. “Boundary Layer Turbulence in Experiments on Quasi Keplerian Flows.” Journal of Fluid Mechanics, vol. 817, Cambridge University Press, 2017, pp. 21–34, doi:10.1017/jfm.2017.109.","ieee":"J. M. Lopez Alonso and M. Avila, “Boundary layer turbulence in experiments on quasi Keplerian flows,” Journal of Fluid Mechanics, vol. 817. Cambridge University Press, pp. 21–34, 2017.","short":"J.M. Lopez Alonso, M. Avila, Journal of Fluid Mechanics 817 (2017) 21–34.","apa":"Lopez Alonso, J. M., & Avila, M. (2017). Boundary layer turbulence in experiments on quasi Keplerian flows. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2017.109","ama":"Lopez Alonso JM, Avila M. Boundary layer turbulence in experiments on quasi Keplerian flows. Journal of Fluid Mechanics. 2017;817:21-34. doi:10.1017/jfm.2017.109","chicago":"Lopez Alonso, Jose M, and Marc Avila. “Boundary Layer Turbulence in Experiments on Quasi Keplerian Flows.” Journal of Fluid Mechanics. Cambridge University Press, 2017. https://doi.org/10.1017/jfm.2017.109.","ista":"Lopez Alonso JM, Avila M. 2017. Boundary layer turbulence in experiments on quasi Keplerian flows. Journal of Fluid Mechanics. 817, 21–34."},"title":"Boundary layer turbulence in experiments on quasi Keplerian flows","external_id":{"isi":["000398179100006"]},"article_processing_charge":"No","author":[{"first_name":"Jose M","id":"40770848-F248-11E8-B48F-1D18A9856A87","last_name":"Lopez Alonso","orcid":"0000-0002-0384-2022","full_name":"Lopez Alonso, Jose M"},{"full_name":"Avila, Marc","last_name":"Avila","first_name":"Marc"}],"publist_id":"6371","oa":1,"quality_controlled":"1","publisher":"Cambridge University Press","publication":"Journal of Fluid Mechanics","day":"25","year":"2017","isi":1,"date_created":"2018-12-11T11:49:44Z","date_published":"2017-04-25T00:00:00Z","doi":"10.1017/jfm.2017.109","page":"21 - 34","_id":"1021","status":"public","type":"journal_article","date_updated":"2023-09-22T09:39:46Z","department":[{"_id":"BjHo"}],"oa_version":"Submitted Version","abstract":[{"lang":"eng","text":"Most flows in nature and engineering are turbulent because of their large velocities and spatial scales. Laboratory experiments on rotating quasi-Keplerian flows, for which the angular velocity decreases radially but the angular momentum increases, are however laminar at Reynolds numbers exceeding one million. This is in apparent contradiction to direct numerical simulations showing that in these experiments turbulence transition is triggered by the axial boundaries. We here show numerically that as the Reynolds number increases, turbulence becomes progressively confined to the boundary layers and the flow in the bulk fully relaminarizes. Our findings support that turbulence is unlikely to occur in isothermal constant-density quasi-Keplerian flows."}],"intvolume":" 817","month":"04","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1608.05527"}],"scopus_import":"1","language":[{"iso":"eng"}],"publication_status":"published","publication_identifier":{"issn":["00221120"]},"volume":817},{"month":"12","intvolume":" 833","scopus_import":"1","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1705.03720"}],"oa_version":"Submitted Version","abstract":[{"text":"The chaotic dynamics of low-dimensional systems, such as Lorenz or Rössler flows, is guided by the infinity of periodic orbits embedded in their strange attractors. Whether this is also the case for the infinite-dimensional dynamics of Navier–Stokes equations has long been speculated, and is a topic of ongoing study. Periodic and relative periodic solutions have been shown to be involved in transitions to turbulence. Their relevance to turbulent dynamics – specifically, whether periodic orbits play the same role in high-dimensional nonlinear systems like the Navier–Stokes equations as they do in lower-dimensional systems – is the focus of the present investigation. We perform here a detailed study of pipe flow relative periodic orbits with energies and mean dissipations close to turbulent values. We outline several approaches to reduction of the translational symmetry of the system. We study pipe flow in a minimal computational cell at Re=2500, and report a library of invariant solutions found with the aid of the method of slices. Detailed study of the unstable manifolds of a sample of these solutions is consistent with the picture that relative periodic orbits are embedded in the chaotic saddle and that they guide the turbulent dynamics.","lang":"eng"}],"volume":833,"language":[{"iso":"eng"}],"publication_identifier":{"issn":["00221120"]},"publication_status":"published","status":"public","type":"journal_article","_id":"792","department":[{"_id":"BjHo"}],"date_updated":"2023-09-27T12:17:35Z","quality_controlled":"1","publisher":"Cambridge University Press","oa":1,"doi":"10.1017/jfm.2017.699","date_published":"2017-12-25T00:00:00Z","date_created":"2018-12-11T11:48:32Z","page":"274 - 301","day":"25","publication":"Journal of Fluid Mechanics","isi":1,"year":"2017","project":[{"_id":"25636330-B435-11E9-9278-68D0E5697425","name":"ROOTS Genome-wide Analysis of Root Traits","grant_number":"11-NSF-1070"}],"title":"Relative periodic orbits form the backbone of turbulent pipe flow","publist_id":"6862","author":[{"id":"3EA1010E-F248-11E8-B48F-1D18A9856A87","first_name":"Nazmi B","orcid":"0000-0003-0423-5010","full_name":"Budanur, Nazmi B","last_name":"Budanur"},{"last_name":"Short","full_name":"Short, Kimberly","first_name":"Kimberly"},{"first_name":"Mohammad","full_name":"Farazmand, Mohammad","last_name":"Farazmand"},{"last_name":"Willis","full_name":"Willis, Ashley","first_name":"Ashley"},{"last_name":"Cvitanović","full_name":"Cvitanović, Predrag","first_name":"Predrag"}],"article_processing_charge":"No","external_id":{"isi":["000414641700001"]},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"ista":"Budanur NB, Short K, Farazmand M, Willis A, Cvitanović P. 2017. Relative periodic orbits form the backbone of turbulent pipe flow. Journal of Fluid Mechanics. 833, 274–301.","chicago":"Budanur, Nazmi B, Kimberly Short, Mohammad Farazmand, Ashley Willis, and Predrag Cvitanović. “Relative Periodic Orbits Form the Backbone of Turbulent Pipe Flow.” Journal of Fluid Mechanics. Cambridge University Press, 2017. https://doi.org/10.1017/jfm.2017.699.","ama":"Budanur NB, Short K, Farazmand M, Willis A, Cvitanović P. Relative periodic orbits form the backbone of turbulent pipe flow. Journal of Fluid Mechanics. 2017;833:274-301. doi:10.1017/jfm.2017.699","apa":"Budanur, N. B., Short, K., Farazmand, M., Willis, A., & Cvitanović, P. (2017). Relative periodic orbits form the backbone of turbulent pipe flow. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2017.699","ieee":"N. B. Budanur, K. Short, M. Farazmand, A. Willis, and P. Cvitanović, “Relative periodic orbits form the backbone of turbulent pipe flow,” Journal of Fluid Mechanics, vol. 833. Cambridge University Press, pp. 274–301, 2017.","short":"N.B. Budanur, K. Short, M. Farazmand, A. Willis, P. Cvitanović, Journal of Fluid Mechanics 833 (2017) 274–301.","mla":"Budanur, Nazmi B., et al. “Relative Periodic Orbits Form the Backbone of Turbulent Pipe Flow.” Journal of Fluid Mechanics, vol. 833, Cambridge University Press, 2017, pp. 274–301, doi:10.1017/jfm.2017.699."}},{"doi":"10.1017/jfm.2017.516","date_published":"2017-08-18T00:00:00Z","date_created":"2018-12-11T11:48:42Z","day":"18","publication":"Journal of Fluid Mechanics","isi":1,"year":"2017","quality_controlled":"1","publisher":"Cambridge University Press","oa":1,"title":"Heteroclinic path to spatially localized chaos in pipe flow","author":[{"orcid":"0000-0003-0423-5010","full_name":"Budanur, Nazmi B","last_name":"Budanur","id":"3EA1010E-F248-11E8-B48F-1D18A9856A87","first_name":"Nazmi B"},{"full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof","first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87"}],"publist_id":"6824","external_id":{"isi":["000408326300001"]},"article_processing_charge":"No","user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","citation":{"chicago":"Budanur, Nazmi B, and Björn Hof. “Heteroclinic Path to Spatially Localized Chaos in Pipe Flow.” Journal of Fluid Mechanics. Cambridge University Press, 2017. https://doi.org/10.1017/jfm.2017.516.","ista":"Budanur NB, Hof B. 2017. Heteroclinic path to spatially localized chaos in pipe flow. Journal of Fluid Mechanics. 827, R1.","mla":"Budanur, Nazmi B., and Björn Hof. “Heteroclinic Path to Spatially Localized Chaos in Pipe Flow.” Journal of Fluid Mechanics, vol. 827, R1, Cambridge University Press, 2017, doi:10.1017/jfm.2017.516.","apa":"Budanur, N. B., & Hof, B. (2017). Heteroclinic path to spatially localized chaos in pipe flow. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2017.516","ama":"Budanur NB, Hof B. Heteroclinic path to spatially localized chaos in pipe flow. Journal of Fluid Mechanics. 2017;827. doi:10.1017/jfm.2017.516","short":"N.B. Budanur, B. Hof, Journal of Fluid Mechanics 827 (2017).","ieee":"N. B. Budanur and B. Hof, “Heteroclinic path to spatially localized chaos in pipe flow,” Journal of Fluid Mechanics, vol. 827. Cambridge University Press, 2017."},"article_number":"R1","volume":827,"language":[{"iso":"eng"}],"publication_identifier":{"issn":["00221120"]},"publication_status":"published","month":"08","intvolume":" 827","scopus_import":"1","main_file_link":[{"url":"https://arxiv.org/abs/1703.10484","open_access":"1"}],"oa_version":"Submitted Version","abstract":[{"text":"In shear flows at transitional Reynolds numbers, localized patches of turbulence, known as puffs, coexist with the laminar flow. Recently, Avila et al. (Phys. Rev. Lett., vol. 110, 2013, 224502) discovered two spatially localized relative periodic solutions for pipe flow, which appeared in a saddle-node bifurcation at low Reynolds number. Combining slicing methods for continuous symmetry reduction with Poincaré sections for the first time in a shear flow setting, we compute and visualize the unstable manifold of the lower-branch solution and show that it extends towards the neighbourhood of the upper-branch solution. Surprisingly, this connection even persists far above the bifurcation point and appears to mediate the first stage of the puff generation: amplification of streamwise localized fluctuations. When the state-space trajectories on the unstable manifold reach the vicinity of the upper branch, corresponding fluctuations expand in space and eventually take the usual shape of a puff.","lang":"eng"}],"department":[{"_id":"BjHo"}],"date_updated":"2023-09-26T16:17:43Z","status":"public","type":"journal_article","_id":"824"},{"citation":{"apa":"Xu, D., Warnecke, S., Song, B., Ma, X., & Hof, B. (2017). Transition to turbulence in pulsating pipe flow. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2017.620","ama":"Xu D, Warnecke S, Song B, Ma X, Hof B. Transition to turbulence in pulsating pipe flow. Journal of Fluid Mechanics. 2017;831:418-432. doi:10.1017/jfm.2017.620","short":"D. Xu, S. Warnecke, B. Song, X. Ma, B. Hof, Journal of Fluid Mechanics 831 (2017) 418–432.","ieee":"D. Xu, S. Warnecke, B. Song, X. Ma, and B. Hof, “Transition to turbulence in pulsating pipe flow,” Journal of Fluid Mechanics, vol. 831. Cambridge University Press, pp. 418–432, 2017.","mla":"Xu, Duo, et al. “Transition to Turbulence in Pulsating Pipe Flow.” Journal of Fluid Mechanics, vol. 831, Cambridge University Press, 2017, pp. 418–32, doi:10.1017/jfm.2017.620.","ista":"Xu D, Warnecke S, Song B, Ma X, Hof B. 2017. Transition to turbulence in pulsating pipe flow. Journal of Fluid Mechanics. 831, 418–432.","chicago":"Xu, Duo, Sascha Warnecke, Baofang Song, Xingyu Ma, and Björn Hof. “Transition to Turbulence in Pulsating Pipe Flow.” Journal of Fluid Mechanics. Cambridge University Press, 2017. https://doi.org/10.1017/jfm.2017.620."},"user_id":"c635000d-4b10-11ee-a964-aac5a93f6ac1","author":[{"last_name":"Xu","full_name":"Xu, Duo","id":"3454D55E-F248-11E8-B48F-1D18A9856A87","first_name":"Duo"},{"first_name":"Sascha","full_name":"Warnecke, Sascha","last_name":"Warnecke"},{"last_name":"Song","full_name":"Song, Baofang","first_name":"Baofang"},{"id":"34BADBA6-F248-11E8-B48F-1D18A9856A87","first_name":"Xingyu","orcid":"0000-0002-0179-9737","full_name":"Ma, Xingyu","last_name":"Ma"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof"}],"publist_id":"6922","article_processing_charge":"No","external_id":{"isi":["000412934800005"]},"title":"Transition to turbulence in pulsating pipe flow","project":[{"grant_number":"306589","name":"Decoding the complexity of turbulence at its origin","_id":"25152F3A-B435-11E9-9278-68D0E5697425","call_identifier":"FP7"}],"isi":1,"year":"2017","day":"25","publication":"Journal of Fluid Mechanics","page":"418 - 432","date_published":"2017-11-25T00:00:00Z","doi":"10.1017/jfm.2017.620","date_created":"2018-12-11T11:48:17Z","quality_controlled":"1","publisher":"Cambridge University Press","oa":1,"date_updated":"2023-09-27T12:28:12Z","department":[{"_id":"BjHo"}],"_id":"745","type":"journal_article","status":"public","publication_identifier":{"issn":["00221120"]},"publication_status":"published","language":[{"iso":"eng"}],"volume":831,"ec_funded":1,"abstract":[{"text":"Fluid flows in nature and applications are frequently subject to periodic velocity modulations. Surprisingly, even for the generic case of flow through a straight pipe, there is little consensus regarding the influence of pulsation on the transition threshold to turbulence: while most studies predict a monotonically increasing threshold with pulsation frequency (i.e. Womersley number, ), others observe a decreasing threshold for identical parameters and only observe an increasing threshold at low . In the present study we apply recent advances in the understanding of transition in steady shear flows to pulsating pipe flow. For moderate pulsation amplitudes we find that the first instability encountered is subcritical (i.e. requiring finite amplitude disturbances) and gives rise to localized patches of turbulence ('puffs') analogous to steady pipe flow. By monitoring the impact of pulsation on the lifetime of turbulence we map the onset of turbulence in parameter space. Transition in pulsatile flow can be separated into three regimes. At small Womersley numbers the dynamics is dominated by the decay turbulence suffers during the slower part of the cycle and hence transition is delayed significantly. As shown in this regime thresholds closely agree with estimates based on a quasi-steady flow assumption only taking puff decay rates into account. The transition point predicted in the zero limit equals to the critical point for steady pipe flow offset by the oscillation Reynolds number (i.e. the dimensionless oscillation amplitude). In the high frequency limit on the other hand, puff lifetimes are identical to those in steady pipe flow and hence the transition threshold appears to be unaffected by flow pulsation. In the intermediate frequency regime the transition threshold sharply drops (with increasing ) from the decay dominated (quasi-steady) threshold to the steady pipe flow level.","lang":"eng"}],"oa_version":"Submitted Version","scopus_import":"1","main_file_link":[{"open_access":"1","url":"https://arxiv.org/abs/1709.03738"}],"month":"11","intvolume":" 831"},{"date_updated":"2023-10-10T13:30:03Z","department":[{"_id":"BjHo"}],"_id":"673","status":"public","type":"journal_article","language":[{"iso":"eng"}],"publication_status":"published","publication_identifier":{"issn":["2470-0045"]},"volume":95,"issue":"5","oa_version":"Submitted Version","abstract":[{"lang":"eng","text":"We present a numerical study of wavy supercritical cylindrical Couette flow between counter-rotating cylinders in which the wavy pattern propagates either prograde with the inner cylinder or retrograde opposite the rotation of the inner cylinder. The wave propagation reversals from prograde to retrograde and vice versa occur at distinct values of the inner cylinder Reynolds number when the associated frequency of the wavy instability vanishes. The reversal occurs for both twofold and threefold symmetric wavy vortices. Moreover, the wave propagation reversal only occurs for sufficiently strong counter-rotation. The flow pattern reversal appears to be intrinsic in the system as either periodic boundary conditions or fixed end wall boundary conditions for different system sizes always result in the wave propagation reversal. We present a detailed bifurcation sequence and parameter space diagram with respect to retrograde behavior of wavy flows. The retrograde propagation of the instability occurs when the inner Reynolds number is about two times the outer Reynolds number. The mechanism for the retrograde propagation is associated with the inviscidly unstable region near the inner cylinder and the direction of the global average azimuthal velocity. Flow dynamics, spatio-temporal behavior, global mean angular velocity, and torque of the flow with the wavy pattern are explored."}],"intvolume":" 95","month":"05","main_file_link":[{"url":"https://arxiv.org/pdf/physics/0505164.pdf","open_access":"1"}],"scopus_import":"1","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"apa":"Altmeyer, S., & Lueptow, R. (2017). Wave propagation reversal for wavy vortices in wide gap counter rotating cylindrical Couette flow. Physical Review E. American Physical Society. https://doi.org/10.1103/PhysRevE.95.053103","ama":"Altmeyer S, Lueptow R. Wave propagation reversal for wavy vortices in wide gap counter rotating cylindrical Couette flow. Physical Review E. 2017;95(5). doi:10.1103/PhysRevE.95.053103","short":"S. Altmeyer, R. Lueptow, Physical Review E 95 (2017).","ieee":"S. Altmeyer and R. Lueptow, “Wave propagation reversal for wavy vortices in wide gap counter rotating cylindrical Couette flow,” Physical Review E, vol. 95, no. 5. American Physical Society, 2017.","mla":"Altmeyer, Sebastian, and Richard Lueptow. “Wave Propagation Reversal for Wavy Vortices in Wide Gap Counter Rotating Cylindrical Couette Flow.” Physical Review E, vol. 95, no. 5, 053103, American Physical Society, 2017, doi:10.1103/PhysRevE.95.053103.","ista":"Altmeyer S, Lueptow R. 2017. Wave propagation reversal for wavy vortices in wide gap counter rotating cylindrical Couette flow. Physical Review E. 95(5), 053103.","chicago":"Altmeyer, Sebastian, and Richard Lueptow. “Wave Propagation Reversal for Wavy Vortices in Wide Gap Counter Rotating Cylindrical Couette Flow.” Physical Review E. American Physical Society, 2017. https://doi.org/10.1103/PhysRevE.95.053103."},"title":"Wave propagation reversal for wavy vortices in wide gap counter rotating cylindrical Couette flow","article_processing_charge":"No","author":[{"first_name":"Sebastian","id":"2EE67FDC-F248-11E8-B48F-1D18A9856A87","last_name":"Altmeyer","orcid":"0000-0001-5964-0203","full_name":"Altmeyer, Sebastian"},{"first_name":"Richard","full_name":"Lueptow, Richard","last_name":"Lueptow"}],"publist_id":"7049","article_number":"053103","publication":"Physical Review E","day":"10","year":"2017","date_created":"2018-12-11T11:47:50Z","date_published":"2017-05-10T00:00:00Z","doi":"10.1103/PhysRevE.95.053103","oa":1,"publisher":"American Physical Society"},{"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"ista":"Altmeyer S, Do Y, Ryu S. 2017. Transient behavior between multi-cell flow states in ferrofluidic Taylor-Couette flow. Chaos. 27(11), 113112.","chicago":"Altmeyer, Sebastian, Younghae Do, and Soorok Ryu. “Transient Behavior between Multi-Cell Flow States in Ferrofluidic Taylor-Couette Flow.” Chaos. AIP Publishing, 2017. https://doi.org/10.1063/1.5002771.","short":"S. Altmeyer, Y. Do, S. Ryu, Chaos 27 (2017).","ieee":"S. Altmeyer, Y. Do, and S. Ryu, “Transient behavior between multi-cell flow states in ferrofluidic Taylor-Couette flow,” Chaos, vol. 27, no. 11. AIP Publishing, 2017.","apa":"Altmeyer, S., Do, Y., & Ryu, S. (2017). Transient behavior between multi-cell flow states in ferrofluidic Taylor-Couette flow. Chaos. AIP Publishing. https://doi.org/10.1063/1.5002771","ama":"Altmeyer S, Do Y, Ryu S. Transient behavior between multi-cell flow states in ferrofluidic Taylor-Couette flow. Chaos. 2017;27(11). doi:10.1063/1.5002771","mla":"Altmeyer, Sebastian, et al. “Transient Behavior between Multi-Cell Flow States in Ferrofluidic Taylor-Couette Flow.” Chaos, vol. 27, no. 11, 113112, AIP Publishing, 2017, doi:10.1063/1.5002771."},"title":"Transient behavior between multi-cell flow states in ferrofluidic Taylor-Couette flow","author":[{"id":"2EE67FDC-F248-11E8-B48F-1D18A9856A87","first_name":"Sebastian","last_name":"Altmeyer","orcid":"0000-0001-5964-0203","full_name":"Altmeyer, Sebastian"},{"first_name":"Younghae","full_name":"Do, Younghae","last_name":"Do"},{"first_name":"Soorok","full_name":"Ryu, Soorok","last_name":"Ryu"}],"publist_id":"7358","article_processing_charge":"No","article_number":"113112","day":"01","publication":"Chaos","has_accepted_license":"1","year":"2017","doi":"10.1063/1.5002771","date_published":"2017-11-01T00:00:00Z","date_created":"2018-12-11T11:46:37Z","publisher":"AIP Publishing","quality_controlled":"1","oa":1,"ddc":["530"],"date_updated":"2024-02-28T13:02:12Z","file_date_updated":"2020-07-14T12:46:32Z","department":[{"_id":"BjHo"}],"_id":"463","status":"public","article_type":"original","type":"journal_article","file":[{"date_updated":"2020-07-14T12:46:32Z","file_size":7714020,"creator":"dernst","date_created":"2019-10-24T15:14:30Z","file_name":"2017_Chaos_Altmeyer.pdf","content_type":"application/pdf","access_level":"open_access","relation":"main_file","file_id":"6970","checksum":"0731f9d416760c1062db258ca51f8bdc"}],"language":[{"iso":"eng"}],"publication_identifier":{"issn":["10541500"]},"publication_status":"published","issue":"11","volume":27,"oa_version":"Published Version","abstract":[{"lang":"eng","text":"We investigate transient behaviors induced by magnetic fields on the dynamics of the flow of a ferrofluid in the gap between two concentric, independently rotating cylinders. Without applying any magnetic fields, we uncover emergence of flow states constituted by a combination of a localized spiral state (SPIl) in the top and bottom of the annulus and different multi-cell flow states (SPI2v, SPI3v) with toroidally closed vortices in the interior of the bulk (SPIl+2v = SPIl + SPI2v and SPIl+3v = SPIl + SPI3v). However, when a magnetic field is presented, we observe the transient behaviors between multi-cell states passing through two critical thresholds in a strength of an axial (transverse) magnetic field. Before the first critical threshold of a magnetic field strength, multi-stable states with different number of cells could be observed. After the first critical threshold, we find the transient behavior between the three- and two-cell flow states. For more strength of magnetic field or after the second critical threshold, we discover that multi-cell states are disappeared and a localized spiral state remains to be stimulated. The studied transient behavior could be understood by the investigation of various quantities including a modal kinetic energy, a mode amplitude of the radial velocity, wavenumber, angular momentum, and torque. In addition, the emergence of new flow states and the transient behavior between their states in ferrofluidic flows indicate that richer and potentially controllable dynamics through magnetic fields could be possible in ferrofluic flow."}],"month":"11","intvolume":" 27","scopus_import":"1"},{"status":"public","type":"journal_article","_id":"661","department":[{"_id":"CaHe"},{"_id":"BjHo"},{"_id":"Bio"}],"date_updated":"2024-03-27T23:30:38Z","month":"03","intvolume":" 19","scopus_import":1,"main_file_link":[{"url":"https://europepmc.org/articles/pmc5635970","open_access":"1"}],"pmid":1,"oa_version":"Submitted Version","abstract":[{"text":"During embryonic development, mechanical forces are essential for cellular rearrangements driving tissue morphogenesis. Here, we show that in the early zebrafish embryo, friction forces are generated at the interface between anterior axial mesoderm (prechordal plate, ppl) progenitors migrating towards the animal pole and neurectoderm progenitors moving in the opposite direction towards the vegetal pole of the embryo. These friction forces lead to global rearrangement of cells within the neurectoderm and determine the position of the neural anlage. Using a combination of experiments and simulations, we show that this process depends on hydrodynamic coupling between neurectoderm and ppl as a result of E-cadherin-mediated adhesion between those tissues. Our data thus establish the emergence of friction forces at the interface between moving tissues as a critical force-generating process shaping the embryo.","lang":"eng"}],"acknowledged_ssus":[{"_id":"SSU"}],"related_material":{"record":[{"id":"50","status":"public","relation":"dissertation_contains"},{"id":"8350","status":"public","relation":"dissertation_contains"}]},"volume":19,"ec_funded":1,"language":[{"iso":"eng"}],"publication_identifier":{"issn":["14657392"]},"publication_status":"published","project":[{"name":"Decoding the complexity of turbulence at its origin","grant_number":"306589","call_identifier":"FP7","_id":"25152F3A-B435-11E9-9278-68D0E5697425"},{"_id":"252ABD0A-B435-11E9-9278-68D0E5697425","call_identifier":"FWF","grant_number":"I 930-B20","name":"Control of Epithelial Cell Layer Spreading in Zebrafish"}],"title":"Friction forces position the neural anlage","author":[{"full_name":"Smutny, Michael","orcid":"0000-0002-5920-9090","last_name":"Smutny","first_name":"Michael","id":"3FE6E4E8-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Ákos","full_name":"Ákos, Zsuzsa","first_name":"Zsuzsa"},{"first_name":"Silvia","last_name":"Grigolon","full_name":"Grigolon, Silvia"},{"id":"40B34FE2-F248-11E8-B48F-1D18A9856A87","first_name":"Shayan","last_name":"Shamipour","full_name":"Shamipour, Shayan"},{"full_name":"Ruprecht, Verena","last_name":"Ruprecht","first_name":"Verena"},{"last_name":"Capek","orcid":"0000-0001-5199-9940","full_name":"Capek, Daniel","first_name":"Daniel","id":"31C42484-F248-11E8-B48F-1D18A9856A87"},{"id":"3ECECA3A-F248-11E8-B48F-1D18A9856A87","first_name":"Martin","full_name":"Behrndt, Martin","last_name":"Behrndt"},{"last_name":"Papusheva","full_name":"Papusheva, Ekaterina","first_name":"Ekaterina","id":"41DB591E-F248-11E8-B48F-1D18A9856A87"},{"full_name":"Tada, Masazumi","last_name":"Tada","first_name":"Masazumi"},{"last_name":"Hof","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn"},{"first_name":"Tamás","last_name":"Vicsek","full_name":"Vicsek, Tamás"},{"first_name":"Guillaume","full_name":"Salbreux, Guillaume","last_name":"Salbreux"},{"first_name":"Carl-Philipp J","id":"39427864-F248-11E8-B48F-1D18A9856A87","last_name":"Heisenberg","orcid":"0000-0002-0912-4566","full_name":"Heisenberg, Carl-Philipp J"}],"publist_id":"7074","external_id":{"pmid":["28346437"]},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"ista":"Smutny M, Ákos Z, Grigolon S, Shamipour S, Ruprecht V, Capek D, Behrndt M, Papusheva E, Tada M, Hof B, Vicsek T, Salbreux G, Heisenberg C-PJ. 2017. Friction forces position the neural anlage. Nature Cell Biology. 19, 306–317.","chicago":"Smutny, Michael, Zsuzsa Ákos, Silvia Grigolon, Shayan Shamipour, Verena Ruprecht, Daniel Capek, Martin Behrndt, et al. “Friction Forces Position the Neural Anlage.” Nature Cell Biology. Nature Publishing Group, 2017. https://doi.org/10.1038/ncb3492.","apa":"Smutny, M., Ákos, Z., Grigolon, S., Shamipour, S., Ruprecht, V., Capek, D., … Heisenberg, C.-P. J. (2017). Friction forces position the neural anlage. Nature Cell Biology. Nature Publishing Group. https://doi.org/10.1038/ncb3492","ama":"Smutny M, Ákos Z, Grigolon S, et al. Friction forces position the neural anlage. Nature Cell Biology. 2017;19:306-317. doi:10.1038/ncb3492","ieee":"M. Smutny et al., “Friction forces position the neural anlage,” Nature Cell Biology, vol. 19. Nature Publishing Group, pp. 306–317, 2017.","short":"M. Smutny, Z. Ákos, S. Grigolon, S. Shamipour, V. Ruprecht, D. Capek, M. Behrndt, E. Papusheva, M. Tada, B. Hof, T. Vicsek, G. Salbreux, C.-P.J. Heisenberg, Nature Cell Biology 19 (2017) 306–317.","mla":"Smutny, Michael, et al. “Friction Forces Position the Neural Anlage.” Nature Cell Biology, vol. 19, Nature Publishing Group, 2017, pp. 306–17, doi:10.1038/ncb3492."},"publisher":"Nature Publishing Group","quality_controlled":"1","oa":1,"doi":"10.1038/ncb3492","date_published":"2017-03-27T00:00:00Z","date_created":"2018-12-11T11:47:46Z","page":"306 - 317","day":"27","publication":"Nature Cell Biology","year":"2017"},{"project":[{"name":"Decoding the complexity of turbulence at its origin","grant_number":"306589","_id":"25152F3A-B435-11E9-9278-68D0E5697425","call_identifier":"FP7"},{"name":"Astrophysical instability of currents and turbulences","grant_number":"SFB 963 TP A8","_id":"2511D90C-B435-11E9-9278-68D0E5697425"}],"citation":{"ama":"Lemoult GM, Shi L, Avila K, Jalikop SV, Avila M, Hof B. Directed percolation phase transition to sustained turbulence in Couette flow. Nature Physics. 2016;12(3):254-258. doi:10.1038/nphys3675","apa":"Lemoult, G. M., Shi, L., Avila, K., Jalikop, S. V., Avila, M., & Hof, B. (2016). Directed percolation phase transition to sustained turbulence in Couette flow. Nature Physics. Nature Publishing Group. https://doi.org/10.1038/nphys3675","short":"G.M. Lemoult, L. Shi, K. Avila, S.V. Jalikop, M. Avila, B. Hof, Nature Physics 12 (2016) 254–258.","ieee":"G. M. Lemoult, L. Shi, K. Avila, S. V. Jalikop, M. Avila, and B. Hof, “Directed percolation phase transition to sustained turbulence in Couette flow,” Nature Physics, vol. 12, no. 3. Nature Publishing Group, pp. 254–258, 2016.","mla":"Lemoult, Grégoire M., et al. “Directed Percolation Phase Transition to Sustained Turbulence in Couette Flow.” Nature Physics, vol. 12, no. 3, Nature Publishing Group, 2016, pp. 254–58, doi:10.1038/nphys3675.","ista":"Lemoult GM, Shi L, Avila K, Jalikop SV, Avila M, Hof B. 2016. Directed percolation phase transition to sustained turbulence in Couette flow. Nature Physics. 12(3), 254–258.","chicago":"Lemoult, Grégoire M, Liang Shi, Kerstin Avila, Shreyas V Jalikop, Marc Avila, and Björn Hof. “Directed Percolation Phase Transition to Sustained Turbulence in Couette Flow.” Nature Physics. Nature Publishing Group, 2016. https://doi.org/10.1038/nphys3675."},"user_id":"3E5EF7F0-F248-11E8-B48F-1D18A9856A87","publist_id":"5685","author":[{"id":"4787FE80-F248-11E8-B48F-1D18A9856A87","first_name":"Grégoire M","last_name":"Lemoult","full_name":"Lemoult, Grégoire M"},{"id":"374A3F1A-F248-11E8-B48F-1D18A9856A87","first_name":"Liang","full_name":"Shi, Liang","last_name":"Shi"},{"first_name":"Kerstin","full_name":"Avila, Kerstin","last_name":"Avila"},{"id":"44A1D772-F248-11E8-B48F-1D18A9856A87","first_name":"Shreyas V","last_name":"Jalikop","full_name":"Jalikop, Shreyas V"},{"full_name":"Avila, Marc","last_name":"Avila","first_name":"Marc"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754"}],"title":"Directed percolation phase transition to sustained turbulence in Couette flow","acknowledgement":"We thank P. Maier for providing valuable ideas and supporting us in the technical aspects. Discussions with D. Barkley, Y. Duguet, B. Eckhart, N. Goldenfeld, P. Manneville and K. Takeuchi are gratefully acknowledged. We acknowledge the Deutsche Forschungsgemeinschaft (Project No. FOR 1182), and the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement 306589 for financial support. L.S. and B.H. acknowledge research funding by Deutsche Forschungsgemeinschaft (DFG) under Grant No. SFB 963/1 (project A8). Numerical simulations were performed thanks to the CPU time allocations of JUROPA in Juelich Supercomputing Center (project HGU17) and of the Max Planck Computing and Data Facility (Garching, Germany). Excellent technical support from M. Rampp on the hybrid code nsCouette is appreciated.","quality_controlled":"1","publisher":"Nature Publishing Group","year":"2016","day":"15","publication":"Nature Physics","page":"254 - 258","date_published":"2016-02-15T00:00:00Z","doi":"10.1038/nphys3675","date_created":"2018-12-11T11:52:21Z","_id":"1494","type":"journal_article","status":"public","date_updated":"2021-01-12T06:51:08Z","department":[{"_id":"BjHo"}],"abstract":[{"lang":"eng","text":"Turbulence is one of the most frequently encountered non-equilibrium phenomena in nature, yet characterizing the transition that gives rise to turbulence in basic shear flows has remained an elusive task. Although, in recent studies, critical points marking the onset of sustained turbulence have been determined for several such flows, the physical nature of the transition could not be fully explained. In extensive experimental and computational studies we show for the example of Couette flow that the onset of turbulence is a second-order phase transition and falls into the directed percolation universality class. Consequently, the complex laminar–turbulent patterns distinctive for the onset of turbulence in shear flows result from short-range interactions of turbulent domains and are characterized by universal critical exponents. More generally, our study demonstrates that even high-dimensional systems far from equilibrium such as turbulence exhibit universality at onset and that here the collective dynamics obeys simple rules."}],"oa_version":"None","scopus_import":1,"month":"02","intvolume":" 12","publication_status":"published","language":[{"iso":"eng"}],"issue":"3","volume":12,"ec_funded":1},{"_id":"1589","pubrep_id":"472","status":"public","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"type":"journal_article","article_type":"original","ddc":["530","540"],"date_updated":"2021-01-12T06:51:48Z","file_date_updated":"2020-07-14T12:45:03Z","department":[{"_id":"BjHo"}],"oa_version":"Published Version","abstract":[{"lang":"eng","text":"We investigate the dynamics of ferrofluidic wavy vortex flows in the counter-rotating Taylor-Couette system, with a focus on wavy flows with a mixture of the dominant azimuthal modes. Without external magnetic field flows are stable and pro-grade with respect to the rotation of the inner cylinder. More complex behaviors can arise when an axial or a transverse magnetic field is applied. Depending on the direction and strength of the field, multi-stable wavy states and bifurcations can occur. We uncover the phenomenon of flow pattern reversal as the strength of the magnetic field is increased through a critical value. In between the regimes of pro-grade and retrograde flow rotations, standing waves with zero angular velocities can emerge. A striking finding is that, under a transverse magnetic field, a second reversal in the flow pattern direction can occur, where the flow pattern evolves into pro-grade rotation again from a retrograde state. Flow reversal is relevant to intriguing phenomena in nature such as geomagnetic reversal. Our results suggest that, in ferrofluids, flow pattern reversal can be induced by varying a magnetic field in a controlled manner, which can be realized in laboratory experiments with potential applications in the development of modern fluid devices."}],"intvolume":" 5","month":"12","scopus_import":1,"language":[{"iso":"eng"}],"file":[{"checksum":"927e151674347661ce36eae2818dafdc","file_id":"5036","content_type":"application/pdf","access_level":"open_access","relation":"main_file","date_created":"2018-12-12T10:13:49Z","file_name":"IST-2016-472-v1+1_srep18589.pdf","date_updated":"2020-07-14T12:45:03Z","file_size":2771236,"creator":"system"}],"publication_status":"published","volume":5,"article_number":"18589","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"chicago":"Altmeyer, Sebastian, Younghae Do, and Ying Lai. “Magnetic Field Induced Flow Pattern Reversal in a Ferrofluidic Taylor-Couette System.” Scientific Reports. Nature Publishing Group, 2015. https://doi.org/10.1038/srep18589.","ista":"Altmeyer S, Do Y, Lai Y. 2015. Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette system. Scientific Reports. 5, 18589.","mla":"Altmeyer, Sebastian, et al. “Magnetic Field Induced Flow Pattern Reversal in a Ferrofluidic Taylor-Couette System.” Scientific Reports, vol. 5, 18589, Nature Publishing Group, 2015, doi:10.1038/srep18589.","ieee":"S. Altmeyer, Y. Do, and Y. Lai, “Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette system,” Scientific Reports, vol. 5. Nature Publishing Group, 2015.","short":"S. Altmeyer, Y. Do, Y. Lai, Scientific Reports 5 (2015).","apa":"Altmeyer, S., Do, Y., & Lai, Y. (2015). Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette system. Scientific Reports. Nature Publishing Group. https://doi.org/10.1038/srep18589","ama":"Altmeyer S, Do Y, Lai Y. Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette system. Scientific Reports. 2015;5. doi:10.1038/srep18589"},"title":"Magnetic field induced flow pattern reversal in a ferrofluidic Taylor-Couette system","author":[{"last_name":"Altmeyer","full_name":"Altmeyer, Sebastian","orcid":"0000-0001-5964-0203","id":"2EE67FDC-F248-11E8-B48F-1D18A9856A87","first_name":"Sebastian"},{"full_name":"Do, Younghae","last_name":"Do","first_name":"Younghae"},{"full_name":"Lai, Ying","last_name":"Lai","first_name":"Ying"}],"publist_id":"5582","oa":1,"publisher":"Nature Publishing Group","quality_controlled":"1","publication":"Scientific Reports","day":"21","year":"2015","has_accepted_license":"1","date_created":"2018-12-11T11:52:53Z","date_published":"2015-12-21T00:00:00Z","doi":"10.1038/srep18589"},{"citation":{"chicago":"Altmeyer, Sebastian, Younghae Do, and Ying Lai. “Ring-Bursting Behavior En Route to Turbulence in Narrow-Gap Taylor-Couette Flows.” Physical Review E. American Physical Society, 2015. https://doi.org/10.1103/PhysRevE.92.053018.","ista":"Altmeyer S, Do Y, Lai Y. 2015. Ring-bursting behavior en route to turbulence in narrow-gap Taylor-Couette flows. Physical Review E. 92(5), 053018.","mla":"Altmeyer, Sebastian, et al. “Ring-Bursting Behavior En Route to Turbulence in Narrow-Gap Taylor-Couette Flows.” Physical Review E, vol. 92, no. 5, 053018, American Physical Society, 2015, doi:10.1103/PhysRevE.92.053018.","apa":"Altmeyer, S., Do, Y., & Lai, Y. (2015). Ring-bursting behavior en route to turbulence in narrow-gap Taylor-Couette flows. Physical Review E. American Physical Society. https://doi.org/10.1103/PhysRevE.92.053018","ama":"Altmeyer S, Do Y, Lai Y. Ring-bursting behavior en route to turbulence in narrow-gap Taylor-Couette flows. Physical Review E. 2015;92(5). doi:10.1103/PhysRevE.92.053018","short":"S. Altmeyer, Y. Do, Y. Lai, Physical Review E 92 (2015).","ieee":"S. Altmeyer, Y. Do, and Y. Lai, “Ring-bursting behavior en route to turbulence in narrow-gap Taylor-Couette flows,” Physical Review E, vol. 92, no. 5. American Physical Society, 2015."},"date_updated":"2021-01-12T06:51:47Z","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","author":[{"id":"2EE67FDC-F248-11E8-B48F-1D18A9856A87","first_name":"Sebastian","last_name":"Altmeyer","orcid":"0000-0001-5964-0203","full_name":"Altmeyer, Sebastian"},{"last_name":"Do","full_name":"Do, Younghae","first_name":"Younghae"},{"full_name":"Lai, Ying","last_name":"Lai","first_name":"Ying"}],"publist_id":"5583","title":"Ring-bursting behavior en route to turbulence in narrow-gap Taylor-Couette flows","department":[{"_id":"BjHo"}],"_id":"1588","article_number":"053018","type":"journal_article","status":"public","year":"2015","publication_status":"published","day":"24","language":[{"iso":"eng"}],"publication":"Physical Review E","volume":92,"issue":"5","date_published":"2015-11-24T00:00:00Z","doi":"10.1103/PhysRevE.92.053018","date_created":"2018-12-11T11:52:53Z","abstract":[{"lang":"eng","text":"We investigate the Taylor-Couette system where the radius ratio is close to unity. Systematically increasing the Reynolds number, we observe a number of previously known transitions, such as one from the classical Taylor vortex flow (TVF) to wavy vortex flow (WVF) and the transition to fully developed turbulence. Prior to the onset of turbulence, we observe intermittent bursting patterns of localized turbulent patches, confirming the experimentally observed pattern of very short wavelength bursts (VSWBs). A striking finding is that, for a Reynolds number larger than that for the onset of VSWBs, a new type of intermittently bursting behavior emerges: patterns of azimuthally closed rings of various orders. We call them ring-bursting patterns, which surround the cylinder completely but remain localized and separated in the axial direction through nonturbulent wavy structures. We employ a number of quantitative measures including the cross-flow energy to characterize the ring-bursting patterns and to distinguish them from the background flow. These patterns are interesting because they do not occur in the wide-gap Taylor-Couette flow systems. The narrow-gap regime is less studied but certainly deserves further attention to gain deeper insights into complex flow dynamics in fluids."}],"oa_version":"None","quality_controlled":"1","scopus_import":1,"publisher":"American Physical Society","month":"11","intvolume":" 92"},{"acknowledgement":"We acknowledge the Deutsche Forschungsgemeinschaft (Project No. FOR 1182), and the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement 306589 for financial support. B.S. acknowledges financial support from the Chinese State Scholarship Fund under grant number 2010629145. B.S. acknowledges support from the International Max Planck Research School for the Physics of Biological and Complex Systems and the Göttingen Graduate School for Neurosciences and Molecular Biosciences. We acknowledge computing resources from GWDG (Gesellschaft für wissenschaftliche Datenverarbeitung Göttingen) and the Jülich Supercomputing Centre (grant HGU16) where the simulations were performed.","oa":1,"quality_controlled":"1","publisher":"Nature Publishing Group","year":"2015","publication":"Nature","day":"21","page":"550 - 553","date_created":"2018-12-11T11:53:20Z","doi":"10.1038/nature15701","date_published":"2015-10-21T00:00:00Z","project":[{"grant_number":"306589","name":"Decoding the complexity of turbulence at its origin","call_identifier":"FP7","_id":"25152F3A-B435-11E9-9278-68D0E5697425"}],"citation":{"mla":"Barkley, Dwight, et al. “The Rise of Fully Turbulent Flow.” Nature, vol. 526, no. 7574, Nature Publishing Group, 2015, pp. 550–53, doi:10.1038/nature15701.","apa":"Barkley, D., Song, B., Vasudevan, M., Lemoult, G. M., Avila, M., & Hof, B. (2015). The rise of fully turbulent flow. Nature. Nature Publishing Group. https://doi.org/10.1038/nature15701","ama":"Barkley D, Song B, Vasudevan M, Lemoult GM, Avila M, Hof B. The rise of fully turbulent flow. Nature. 2015;526(7574):550-553. doi:10.1038/nature15701","short":"D. Barkley, B. Song, M. Vasudevan, G.M. Lemoult, M. Avila, B. Hof, Nature 526 (2015) 550–553.","ieee":"D. Barkley, B. Song, M. Vasudevan, G. M. Lemoult, M. Avila, and B. Hof, “The rise of fully turbulent flow,” Nature, vol. 526, no. 7574. Nature Publishing Group, pp. 550–553, 2015.","chicago":"Barkley, Dwight, Baofang Song, Mukund Vasudevan, Grégoire M Lemoult, Marc Avila, and Björn Hof. “The Rise of Fully Turbulent Flow.” Nature. Nature Publishing Group, 2015. https://doi.org/10.1038/nature15701.","ista":"Barkley D, Song B, Vasudevan M, Lemoult GM, Avila M, Hof B. 2015. The rise of fully turbulent flow. Nature. 526(7574), 550–553."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","publist_id":"5485","author":[{"first_name":"Dwight","last_name":"Barkley","full_name":"Barkley, Dwight"},{"full_name":"Song, Baofang","last_name":"Song","first_name":"Baofang"},{"last_name":"Vasudevan","full_name":"Vasudevan, Mukund","id":"3C5A959A-F248-11E8-B48F-1D18A9856A87","first_name":"Mukund"},{"id":"4787FE80-F248-11E8-B48F-1D18A9856A87","first_name":"Grégoire M","full_name":"Lemoult, Grégoire M","last_name":"Lemoult"},{"first_name":"Marc","full_name":"Avila, Marc","last_name":"Avila"},{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","last_name":"Hof","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn"}],"title":"The rise of fully turbulent flow","abstract":[{"text":"Over a century of research into the origin of turbulence in wall-bounded shear flows has resulted in a puzzling picture in which turbulence appears in a variety of different states competing with laminar background flow. At moderate flow speeds, turbulence is confined to localized patches; it is only at higher speeds that the entire flow becomes turbulent. The origin of the different states encountered during this transition, the front dynamics of the turbulent regions and the transformation to full turbulence have yet to be explained. By combining experiments, theory and computer simulations, here we uncover a bifurcation scenario that explains the transformation to fully turbulent pipe flow and describe the front dynamics of the different states encountered in the process. Key to resolving this problem is the interpretation of the flow as a bistable system with nonlinear propagation (advection) of turbulent fronts. These findings bridge the gap between our understanding of the onset of turbulence and fully turbulent flows.","lang":"eng"}],"oa_version":"Preprint","main_file_link":[{"url":"http://arxiv.org/abs/1510.09143","open_access":"1"}],"scopus_import":1,"intvolume":" 526","month":"10","publication_status":"published","language":[{"iso":"eng"}],"ec_funded":1,"volume":526,"issue":"7574","_id":"1664","type":"journal_article","status":"public","date_updated":"2021-01-12T06:52:22Z","department":[{"_id":"BjHo"}]},{"file":[{"date_created":"2018-12-12T10:13:35Z","file_name":"IST-2017-748-v1+1_1.4930850.pdf","date_updated":"2020-07-14T12:45:12Z","file_size":872366,"creator":"system","file_id":"5019","checksum":"604bba3c2496aadb3efcff77de01ce6c","content_type":"application/pdf","access_level":"open_access","relation":"main_file"}],"language":[{"iso":"eng"}],"publication_status":"published","issue":"9","volume":27,"oa_version":"Published Version","month":"09","intvolume":" 27","scopus_import":1,"ddc":["532"],"date_updated":"2021-01-12T06:52:28Z","file_date_updated":"2020-07-14T12:45:12Z","department":[{"_id":"BjHo"}],"_id":"1679","status":"public","pubrep_id":"748","type":"journal_article","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"day":"24","publication":"Physics of Fluids","has_accepted_license":"1","year":"2015","date_published":"2015-09-24T00:00:00Z","doi":"10.1063/1.4930850","date_created":"2018-12-11T11:53:26Z","publisher":"American Institute of Physics","quality_controlled":"1","oa":1,"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"ista":"Lemoult GM, Maier P, Hof B. 2015. Taylor’s Forest. Physics of Fluids. 27(9), 091102.","chicago":"Lemoult, Grégoire M, Philipp Maier, and Björn Hof. “Taylor’s Forest.” Physics of Fluids. American Institute of Physics, 2015. https://doi.org/10.1063/1.4930850.","short":"G.M. Lemoult, P. Maier, B. Hof, Physics of Fluids 27 (2015).","ieee":"G. M. Lemoult, P. Maier, and B. Hof, “Taylor’s Forest,” Physics of Fluids, vol. 27, no. 9. American Institute of Physics, 2015.","apa":"Lemoult, G. M., Maier, P., & Hof, B. (2015). Taylor’s Forest. Physics of Fluids. American Institute of Physics. https://doi.org/10.1063/1.4930850","ama":"Lemoult GM, Maier P, Hof B. Taylor’s Forest. Physics of Fluids. 2015;27(9). doi:10.1063/1.4930850","mla":"Lemoult, Grégoire M., et al. “Taylor’s Forest.” Physics of Fluids, vol. 27, no. 9, 091102, American Institute of Physics, 2015, doi:10.1063/1.4930850."},"title":"Taylor's Forest","author":[{"first_name":"Grégoire M","id":"4787FE80-F248-11E8-B48F-1D18A9856A87","full_name":"Lemoult, Grégoire M","last_name":"Lemoult"},{"full_name":"Maier, Philipp","last_name":"Maier","first_name":"Philipp","id":"384F7C04-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87"}],"publist_id":"5469","article_number":"091102"},{"oa":1,"quality_controlled":"1","publisher":"Nature Publishing Group","year":"2015","has_accepted_license":"1","publication":"Scientific Reports","day":"12","date_created":"2018-12-11T11:54:06Z","date_published":"2015-06-12T00:00:00Z","doi":"10.1038/srep10781","article_number":"10781","citation":{"short":"S. Altmeyer, Y. Do, Y. Lai, Scientific Reports 5 (2015).","ieee":"S. Altmeyer, Y. Do, and Y. Lai, “Transition to turbulence in Taylor-Couette ferrofluidic flow,” Scientific Reports, vol. 5. Nature Publishing Group, 2015.","apa":"Altmeyer, S., Do, Y., & Lai, Y. (2015). Transition to turbulence in Taylor-Couette ferrofluidic flow. Scientific Reports. Nature Publishing Group. https://doi.org/10.1038/srep10781","ama":"Altmeyer S, Do Y, Lai Y. Transition to turbulence in Taylor-Couette ferrofluidic flow. Scientific Reports. 2015;5. doi:10.1038/srep10781","mla":"Altmeyer, Sebastian, et al. “Transition to Turbulence in Taylor-Couette Ferrofluidic Flow.” Scientific Reports, vol. 5, 10781, Nature Publishing Group, 2015, doi:10.1038/srep10781.","ista":"Altmeyer S, Do Y, Lai Y. 2015. Transition to turbulence in Taylor-Couette ferrofluidic flow. Scientific Reports. 5, 10781.","chicago":"Altmeyer, Sebastian, Younghae Do, and Ying Lai. “Transition to Turbulence in Taylor-Couette Ferrofluidic Flow.” Scientific Reports. Nature Publishing Group, 2015. https://doi.org/10.1038/srep10781."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","author":[{"full_name":"Altmeyer, Sebastian","orcid":"0000-0001-5964-0203","last_name":"Altmeyer","id":"2EE67FDC-F248-11E8-B48F-1D18A9856A87","first_name":"Sebastian"},{"first_name":"Younghae","full_name":"Do, Younghae","last_name":"Do"},{"full_name":"Lai, Ying","last_name":"Lai","first_name":"Ying"}],"publist_id":"5306","title":"Transition to turbulence in Taylor-Couette ferrofluidic flow","abstract":[{"text":"It is known that in classical fluids turbulence typically occurs at high Reynolds numbers. But can turbulence occur at low Reynolds numbers? Here we investigate the transition to turbulence in the classic Taylor-Couette system in which the rotating fluids are manufactured ferrofluids with magnetized nanoparticles embedded in liquid carriers. We find that, in the presence of a magnetic field transverse to the symmetry axis of the system, turbulence can occur at Reynolds numbers that are at least one order of magnitude smaller than those in conventional fluids. This is established by extensive computational ferrohydrodynamics through a detailed investigation of transitions in the flow structure, and characterization of behaviors of physical quantities such as the energy, the wave number, and the angular momentum through the bifurcations. A finding is that, as the magnetic field is increased, onset of turbulence can be determined accurately and reliably. Our results imply that experimental investigation of turbulence may be feasible by using ferrofluids. Our study of transition to and evolution of turbulence in the Taylor-Couette ferrofluidic flow system provides insights into the challenging problem of turbulence control.","lang":"eng"}],"oa_version":"Published Version","scopus_import":1,"intvolume":" 5","month":"06","publication_status":"published","language":[{"iso":"eng"}],"file":[{"content_type":"application/pdf","relation":"main_file","access_level":"open_access","file_id":"5280","checksum":"7716f582f8c9d82d8f2bf80bf896b440","file_size":2449723,"date_updated":"2020-07-14T12:45:16Z","creator":"system","file_name":"IST-2016-450-v1+1_srep10781.pdf","date_created":"2018-12-12T10:17:26Z"}],"volume":5,"_id":"1804","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"type":"journal_article","pubrep_id":"450","status":"public","date_updated":"2021-01-12T06:53:18Z","ddc":["530"],"department":[{"_id":"BjHo"}],"file_date_updated":"2020-07-14T12:45:16Z"},{"abstract":[{"text":"Transition to turbulence in straight pipes occurs in spite of the linear stability of the laminar Hagen-Poiseuille flow if both the amplitude of flow perturbations and the Reynolds number Re exceed a minimum threshold (subcritical transition). As the pipe curvature increases, centrifugal effects become important, modifying the basic flow as well as the most unstable linear modes. If the curvature (tube-to-coiling diameter d/D) is sufficiently large, a Hopf bifurcation (supercritical instability) is encountered before turbulence can be excited (subcritical instability). We trace the instability thresholds in the Re - d/D parameter space in the range 0.01 ≤ d/D\\ ≤ 0.1 by means of laser-Doppler velocimetry and determine the point where the subcritical and supercritical instabilities meet. Two different experimental set-ups are used: a closed system where the pipe forms an axisymmetric torus and an open system employing a helical pipe. Implications for the measurement of friction factors in curved pipes are discussed.","lang":"eng"}],"oa_version":"Preprint","scopus_import":1,"main_file_link":[{"url":"https://arxiv.org/abs/1508.06559","open_access":"1"}],"month":"04","intvolume":" 770","publication_status":"published","language":[{"iso":"eng"}],"volume":770,"issue":"5","ec_funded":1,"_id":"1837","article_type":"original","type":"journal_article","status":"public","date_updated":"2021-01-12T06:53:31Z","department":[{"_id":"BjHo"}],"quality_controlled":"1","publisher":"Cambridge University Press","oa":1,"year":"2015","day":"08","publication":"Journal of Fluid Mechanics","doi":"10.1017/jfm.2015.184","date_published":"2015-04-08T00:00:00Z","date_created":"2018-12-11T11:54:17Z","article_number":"R3","project":[{"name":"Decoding the complexity of turbulence at its origin","grant_number":"306589","call_identifier":"FP7","_id":"25152F3A-B435-11E9-9278-68D0E5697425"}],"citation":{"ista":"Kühnen J, Braunshier P, Schwegel M, Kuhlmann H, Hof B. 2015. Subcritical versus supercritical transition to turbulence in curved pipes. Journal of Fluid Mechanics. 770(5), R3.","chicago":"Kühnen, Jakob, P Braunshier, M Schwegel, Hendrik Kuhlmann, and Björn Hof. “Subcritical versus Supercritical Transition to Turbulence in Curved Pipes.” Journal of Fluid Mechanics. Cambridge University Press, 2015. https://doi.org/10.1017/jfm.2015.184.","apa":"Kühnen, J., Braunshier, P., Schwegel, M., Kuhlmann, H., & Hof, B. (2015). Subcritical versus supercritical transition to turbulence in curved pipes. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2015.184","ama":"Kühnen J, Braunshier P, Schwegel M, Kuhlmann H, Hof B. Subcritical versus supercritical transition to turbulence in curved pipes. Journal of Fluid Mechanics. 2015;770(5). doi:10.1017/jfm.2015.184","ieee":"J. Kühnen, P. Braunshier, M. Schwegel, H. Kuhlmann, and B. Hof, “Subcritical versus supercritical transition to turbulence in curved pipes,” Journal of Fluid Mechanics, vol. 770, no. 5. Cambridge University Press, 2015.","short":"J. Kühnen, P. Braunshier, M. Schwegel, H. Kuhlmann, B. Hof, Journal of Fluid Mechanics 770 (2015).","mla":"Kühnen, Jakob, et al. “Subcritical versus Supercritical Transition to Turbulence in Curved Pipes.” Journal of Fluid Mechanics, vol. 770, no. 5, R3, Cambridge University Press, 2015, doi:10.1017/jfm.2015.184."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","publist_id":"5265","author":[{"id":"3A47AE32-F248-11E8-B48F-1D18A9856A87","first_name":"Jakob","full_name":"Kühnen, Jakob","orcid":"0000-0003-4312-0179","last_name":"Kühnen"},{"last_name":"Braunshier","full_name":"Braunshier, P","first_name":"P"},{"first_name":"M","full_name":"Schwegel, M","last_name":"Schwegel"},{"first_name":"Hendrik","full_name":"Kuhlmann, Hendrik","last_name":"Kuhlmann"},{"orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof","first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87"}],"article_processing_charge":"No","external_id":{"arxiv":["1508.06559"]},"title":"Subcritical versus supercritical transition to turbulence in curved pipes"},{"author":[{"last_name":"Park","full_name":"Park, Youngyong","first_name":"Youngyong"},{"first_name":"Younghae","full_name":"Do, Younghae","last_name":"Do"},{"orcid":"0000-0001-5964-0203","full_name":"Altmeyer, Sebastian","last_name":"Altmeyer","id":"2EE67FDC-F248-11E8-B48F-1D18A9856A87","first_name":"Sebastian"},{"full_name":"Lai, Yingcheng","last_name":"Lai","first_name":"Yingcheng"},{"first_name":"Gyuwon","full_name":"Lee, Gyuwon","last_name":"Lee"}],"publist_id":"5229","title":"Early effect in time-dependent, high-dimensional nonlinear dynamical systems with multiple resonances","department":[{"_id":"BjHo"}],"date_updated":"2021-01-12T06:53:44Z","citation":{"short":"Y. Park, Y. Do, S. Altmeyer, Y. Lai, G. Lee, Physical Review E 91 (2015).","ieee":"Y. Park, Y. Do, S. Altmeyer, Y. Lai, and G. Lee, “Early effect in time-dependent, high-dimensional nonlinear dynamical systems with multiple resonances,” Physical Review E, vol. 91, no. 2. American Physical Society, 2015.","apa":"Park, Y., Do, Y., Altmeyer, S., Lai, Y., & Lee, G. (2015). Early effect in time-dependent, high-dimensional nonlinear dynamical systems with multiple resonances. Physical Review E. American Physical Society. https://doi.org/10.1103/PhysRevE.91.022906","ama":"Park Y, Do Y, Altmeyer S, Lai Y, Lee G. Early effect in time-dependent, high-dimensional nonlinear dynamical systems with multiple resonances. Physical Review E. 2015;91(2). doi:10.1103/PhysRevE.91.022906","mla":"Park, Youngyong, et al. “Early Effect in Time-Dependent, High-Dimensional Nonlinear Dynamical Systems with Multiple Resonances.” Physical Review E, vol. 91, no. 2, 022906, American Physical Society, 2015, doi:10.1103/PhysRevE.91.022906.","ista":"Park Y, Do Y, Altmeyer S, Lai Y, Lee G. 2015. Early effect in time-dependent, high-dimensional nonlinear dynamical systems with multiple resonances. Physical Review E. 91(2), 022906.","chicago":"Park, Youngyong, Younghae Do, Sebastian Altmeyer, Yingcheng Lai, and Gyuwon Lee. “Early Effect in Time-Dependent, High-Dimensional Nonlinear Dynamical Systems with Multiple Resonances.” Physical Review E. American Physical Society, 2015. https://doi.org/10.1103/PhysRevE.91.022906."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","type":"journal_article","status":"public","_id":"1868","article_number":"022906","date_created":"2018-12-11T11:54:27Z","volume":91,"date_published":"2015-02-09T00:00:00Z","doi":"10.1103/PhysRevE.91.022906","issue":"2","year":"2015","publication_status":"published","publication_identifier":{"issn":["1539-3755"]},"language":[{"iso":"eng"}],"publication":"Physical Review E","day":"09","publisher":"American Physical Society","quality_controlled":"1","scopus_import":1,"intvolume":" 91","month":"02","abstract":[{"lang":"eng","text":"We investigate high-dimensional nonlinear dynamical systems exhibiting multiple resonances under adiabatic parameter variations. Our motivations come from experimental considerations where time-dependent sweeping of parameters is a practical approach to probing and characterizing the bifurcations of the system. The question is whether bifurcations so detected are faithful representations of the bifurcations intrinsic to the original stationary system. Utilizing a harmonically forced, closed fluid flow system that possesses multiple resonances and solving the Navier-Stokes equation under proper boundary conditions, we uncover the phenomenon of the early effect. Specifically, as a control parameter, e.g., the driving frequency, is adiabatically increased from an initial value, resonances emerge at frequency values that are lower than those in the corresponding stationary system. The phenomenon is established by numerical characterization of physical quantities through the resonances, which include the kinetic energy and the vorticity field, and a heuristic analysis based on the concept of instantaneous frequency. A simple formula is obtained which relates the resonance points in the time-dependent and time-independent systems. Our findings suggest that, in general, any true bifurcation of a nonlinear dynamical system can be unequivocally uncovered through adiabatic parameter sweeping, in spite of a shift in the bifurcation point, which is of value to experimental studies of nonlinear dynamical systems."}],"oa_version":"None"},{"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","date_updated":"2021-01-12T06:54:51Z","citation":{"chicago":"Shi, Liang, Markus Rampp, Björn Hof, and Marc Avila. “A Hybrid MPI-OpenMP Parallel Implementation for Pseudospectral Simulations with Application to Taylor-Couette Flow.” Computers and Fluids. Elsevier, 2015. https://doi.org/10.1016/j.compfluid.2014.09.021.","ista":"Shi L, Rampp M, Hof B, Avila M. 2015. A hybrid MPI-OpenMP parallel implementation for pseudospectral simulations with application to Taylor-Couette flow. Computers and Fluids. 106(1), 1–11.","mla":"Shi, Liang, et al. “A Hybrid MPI-OpenMP Parallel Implementation for Pseudospectral Simulations with Application to Taylor-Couette Flow.” Computers and Fluids, vol. 106, no. 1, Elsevier, 2015, pp. 1–11, doi:10.1016/j.compfluid.2014.09.021.","short":"L. Shi, M. Rampp, B. Hof, M. Avila, Computers and Fluids 106 (2015) 1–11.","ieee":"L. Shi, M. Rampp, B. Hof, and M. Avila, “A hybrid MPI-OpenMP parallel implementation for pseudospectral simulations with application to Taylor-Couette flow,” Computers and Fluids, vol. 106, no. 1. Elsevier, pp. 1–11, 2015.","ama":"Shi L, Rampp M, Hof B, Avila M. A hybrid MPI-OpenMP parallel implementation for pseudospectral simulations with application to Taylor-Couette flow. Computers and Fluids. 2015;106(1):1-11. doi:10.1016/j.compfluid.2014.09.021","apa":"Shi, L., Rampp, M., Hof, B., & Avila, M. (2015). A hybrid MPI-OpenMP parallel implementation for pseudospectral simulations with application to Taylor-Couette flow. Computers and Fluids. Elsevier. https://doi.org/10.1016/j.compfluid.2014.09.021"},"title":"A hybrid MPI-OpenMP parallel implementation for pseudospectral simulations with application to Taylor-Couette flow","department":[{"_id":"BjHo"}],"author":[{"last_name":"Shi","full_name":"Shi, Liang","first_name":"Liang","id":"374A3F1A-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Rampp","full_name":"Rampp, Markus","first_name":"Markus"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof"},{"first_name":"Marc","last_name":"Avila","full_name":"Avila, Marc"}],"publist_id":"5042","_id":"2030","status":"public","type":"journal_article","day":"01","language":[{"iso":"eng"}],"publication":"Computers and Fluids","publication_status":"published","year":"2015","date_published":"2015-01-01T00:00:00Z","doi":"10.1016/j.compfluid.2014.09.021","volume":106,"issue":"1","date_created":"2018-12-11T11:55:18Z","page":"1 - 11","oa_version":"Preprint","abstract":[{"text":"A hybrid-parallel direct-numerical-simulation method with application to turbulent Taylor-Couette flow is presented. The Navier-Stokes equations are discretized in cylindrical coordinates with the spectral Fourier-Galerkin method in the axial and azimuthal directions, and high-order finite differences in the radial direction. Time is advanced by a second-order, semi-implicit projection scheme, which requires the solution of five Helmholtz/Poisson equations, avoids staggered grids and renders very small slip velocities. Nonlinear terms are evaluated with the pseudospectral method. The code is parallelized using a hybrid MPI-OpenMP strategy, which, compared with a flat MPI parallelization, is simpler to implement, allows to reduce inter-node communications and MPI overhead that become relevant at high processor-core counts, and helps to contain the memory footprint. A strong scaling study shows that the hybrid code maintains scalability up to more than 20,000 processor cores and thus allows to perform simulations at higher resolutions than previously feasible. In particular, it opens up the possibility to simulate turbulent Taylor-Couette flows at Reynolds numbers up to O(105). This enables to probe hydrodynamic turbulence in Keplerian flows in experimentally relevant regimes.","lang":"eng"}],"month":"01","intvolume":" 106","quality_controlled":"1","scopus_import":1,"publisher":"Elsevier","oa":1,"main_file_link":[{"url":"http://arxiv.org/abs/1311.2481","open_access":"1"}]},{"user_id":"3E5EF7F0-F248-11E8-B48F-1D18A9856A87","citation":{"mla":"Kühnen, Jakob, et al. “Experimental Investigation of Transitional Flow in a Toroidal Pipe.” Journal of Fluid Mechanics, vol. 738, Cambridge University Press, 2014, pp. 463–91, doi:10.1017/jfm.2013.603.","apa":"Kühnen, J., Holzner, M., Hof, B., & Kuhlmann, H. (2014). Experimental investigation of transitional flow in a toroidal pipe. Journal of Fluid Mechanics. Cambridge University Press. https://doi.org/10.1017/jfm.2013.603","ama":"Kühnen J, Holzner M, Hof B, Kuhlmann H. Experimental investigation of transitional flow in a toroidal pipe. Journal of Fluid Mechanics. 2014;738:463-491. doi:10.1017/jfm.2013.603","ieee":"J. Kühnen, M. Holzner, B. Hof, and H. Kuhlmann, “Experimental investigation of transitional flow in a toroidal pipe,” Journal of Fluid Mechanics, vol. 738. Cambridge University Press, pp. 463–491, 2014.","short":"J. Kühnen, M. Holzner, B. Hof, H. Kuhlmann, Journal of Fluid Mechanics 738 (2014) 463–491.","chicago":"Kühnen, Jakob, Markus Holzner, Björn Hof, and Hendrik Kuhlmann. “Experimental Investigation of Transitional Flow in a Toroidal Pipe.” Journal of Fluid Mechanics. Cambridge University Press, 2014. https://doi.org/10.1017/jfm.2013.603.","ista":"Kühnen J, Holzner M, Hof B, Kuhlmann H. 2014. Experimental investigation of transitional flow in a toroidal pipe. Journal of Fluid Mechanics. 738, 463–491."},"title":"Experimental investigation of transitional flow in a toroidal pipe","author":[{"first_name":"Jakob","id":"3A47AE32-F248-11E8-B48F-1D18A9856A87","full_name":"Kühnen, Jakob","orcid":"0000-0003-4312-0179","last_name":"Kühnen"},{"full_name":"Holzner, Markus","last_name":"Holzner","first_name":"Markus"},{"last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn"},{"full_name":"Kuhlmann, Hendrik","last_name":"Kuhlmann","first_name":"Hendrik"}],"publist_id":"5001","external_id":{"arxiv":["1508.06546"]},"article_processing_charge":"No","day":"10","publication":"Journal of Fluid Mechanics","year":"2014","doi":"10.1017/jfm.2013.603","date_published":"2014-01-10T00:00:00Z","date_created":"2018-12-11T11:55:25Z","page":"463 - 491","publisher":"Cambridge University Press","quality_controlled":"1","oa":1,"date_updated":"2021-01-12T06:54:59Z","department":[{"_id":"BjHo"}],"_id":"2050","status":"public","type":"journal_article","language":[{"iso":"eng"}],"publication_status":"published","volume":738,"oa_version":"Submitted Version","abstract":[{"lang":"eng","text":"The flow instability and further transition to turbulence in a toroidal pipe (torus) with curvature ratio (tube-to-coiling diameter) 0.049 is investigated experimentally. The flow inside the toroidal pipe is driven by a steel sphere fitted to the inner pipe diameter. The sphere is moved with constant azimuthal velocity from outside the torus by a moving magnet. The experiment is designed to investigate curved pipe flow by optical measurement techniques. Using stereoscopic particle image velocimetry, laser Doppler velocimetry and pressure drop measurements, the flow is measured for Reynolds numbers ranging from 1000 to 15 000. Time- and space-resolved velocity fields are obtained and analysed. The steady axisymmetric basic flow is strongly influenced by centrifugal effects. On an increase of the Reynolds number we find a sequence of bifurcations. For Re=4075±2% a supercritical bifurcation to an oscillatory flow is found in which waves travel in the streamwise direction with a phase velocity slightly faster than the mean flow. The oscillatory flow is superseded by a presumably quasi-periodic flow at a further increase of the Reynolds number before turbulence sets in. The results are found to be compatible, in general, with earlier experimental and numerical investigations on transition to turbulence in helical and curved pipes. However, important aspects of the bifurcation scenario differ considerably."}],"month":"01","intvolume":" 738","scopus_import":1,"main_file_link":[{"url":"https://arxiv.org/abs/1508.06546","open_access":"1"}]},{"user_id":"4435EBFC-F248-11E8-B48F-1D18A9856A87","citation":{"mla":"Altmeyer, Sebastian. “On Secondary Instabilities Generating Footbridges between Spiral Vortex Flow.” Fluid Dynamics Research, vol. 46, no. 2, 025503, IOP Publishing Ltd., 2014, doi:10.1088/0169-5983/46/2/025503.","apa":"Altmeyer, S. (2014). On secondary instabilities generating footbridges between spiral vortex flow. Fluid Dynamics Research. IOP Publishing Ltd. https://doi.org/10.1088/0169-5983/46/2/025503","ama":"Altmeyer S. On secondary instabilities generating footbridges between spiral vortex flow. Fluid Dynamics Research. 2014;46(2). doi:10.1088/0169-5983/46/2/025503","ieee":"S. Altmeyer, “On secondary instabilities generating footbridges between spiral vortex flow,” Fluid Dynamics Research, vol. 46, no. 2. IOP Publishing Ltd., 2014.","short":"S. Altmeyer, Fluid Dynamics Research 46 (2014).","chicago":"Altmeyer, Sebastian. “On Secondary Instabilities Generating Footbridges between Spiral Vortex Flow.” Fluid Dynamics Research. IOP Publishing Ltd., 2014. https://doi.org/10.1088/0169-5983/46/2/025503.","ista":"Altmeyer S. 2014. On secondary instabilities generating footbridges between spiral vortex flow. Fluid Dynamics Research. 46(2), 025503."},"date_updated":"2021-01-12T06:56:07Z","title":"On secondary instabilities generating footbridges between spiral vortex flow","department":[{"_id":"BjHo"}],"publist_id":"4740","author":[{"last_name":"Altmeyer","orcid":"0000-0001-5964-0203","full_name":"Altmeyer, Sebastian","id":"2EE67FDC-F248-11E8-B48F-1D18A9856A87","first_name":"Sebastian"}],"article_number":"025503","_id":"2224","status":"public","type":"journal_article","day":"01","language":[{"iso":"eng"}],"publication":"Fluid Dynamics Research","publication_identifier":{"issn":["01695983"]},"publication_status":"published","year":"2014","date_published":"2014-04-01T00:00:00Z","doi":"10.1088/0169-5983/46/2/025503","volume":46,"issue":"2","date_created":"2018-12-11T11:56:25Z","oa_version":"None","abstract":[{"lang":"eng","text":"This work investigates the transition between different traveling helical waves (spirals, SPIs) in the setup of differentially independent rotating cylinders. We use direct numerical simulations to consider an infinite long and periodic Taylor-Couette apparatus with fixed axial periodicity length. We find so-called mixed-cross-spirals (MCSs), that can be seen as nonlinear superpositions of SPIs, to establish stable footbridges connecting SPI states. While bridging the bifurcation branches of SPIs, the corresponding contributions within the MCS vary continuously with the control parameters. Here discussed MCSs presenting footbridge solutions start and end in different SPI branches. Therefore they differ significantly from the already known MCSs that present bypass solutions (Altmeyer and Hoffmann 2010 New J. Phys. 12 113035). The latter start and end in the same SPI branch, while they always bifurcate out of those SPI branches with the larger mode amplitude. Meanwhile, these only appear within the coexisting region of both SPIs. In contrast, the footbridge solutions can also bifurcate out of the minor SPI contribution. We also find they exist in regions where only one of the SPIs contributions exists. In addition, MCS as footbridge solution can appear either stable or unstable. The latter detected transient solutions offer similar spatio-temporal characteristics to the flow establishing stable footbridges. Such transition processes are interesting for pattern-forming systems in general because they accomplish transitions between traveling waves of different azimuthal wave numbers and have not been described in the literature yet."}],"month":"04","intvolume":" 46","quality_controlled":"1","scopus_import":1,"publisher":"IOP Publishing Ltd."},{"date_created":"2018-12-11T11:56:28Z","date_published":"2014-02-01T00:00:00Z","doi":"10.1088/1742-5468/2014/02/P02001","publication":"Journal of Statistical Mechanics Theory and Experiment","day":"01","year":"2014","oa":1,"quality_controlled":"1","publisher":"IOP Publishing","title":"Deterministic and stochastic aspects of the transition to turbulence","external_id":{"arxiv":["1403.4516"]},"article_processing_charge":"No","author":[{"full_name":"Song, Baofang","last_name":"Song","id":"a79e57f5-e8a5-11ec-9dc9-83fb8c81cf72","first_name":"Baofang"},{"full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof","first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87"}],"publist_id":"4729","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"chicago":"Song, Baofang, and Björn Hof. “Deterministic and Stochastic Aspects of the Transition to Turbulence.” Journal of Statistical Mechanics Theory and Experiment. IOP Publishing, 2014. https://doi.org/10.1088/1742-5468/2014/02/P02001.","ista":"Song B, Hof B. 2014. Deterministic and stochastic aspects of the transition to turbulence. Journal of Statistical Mechanics Theory and Experiment. 2014(2), P02001.","mla":"Song, Baofang, and Björn Hof. “Deterministic and Stochastic Aspects of the Transition to Turbulence.” Journal of Statistical Mechanics Theory and Experiment, vol. 2014, no. 2, P02001, IOP Publishing, 2014, doi:10.1088/1742-5468/2014/02/P02001.","ieee":"B. Song and B. Hof, “Deterministic and stochastic aspects of the transition to turbulence,” Journal of Statistical Mechanics Theory and Experiment, vol. 2014, no. 2. IOP Publishing, 2014.","short":"B. Song, B. Hof, Journal of Statistical Mechanics Theory and Experiment 2014 (2014).","apa":"Song, B., & Hof, B. (2014). Deterministic and stochastic aspects of the transition to turbulence. Journal of Statistical Mechanics Theory and Experiment. IOP Publishing. https://doi.org/10.1088/1742-5468/2014/02/P02001","ama":"Song B, Hof B. Deterministic and stochastic aspects of the transition to turbulence. Journal of Statistical Mechanics Theory and Experiment. 2014;2014(2). doi:10.1088/1742-5468/2014/02/P02001"},"article_number":"P02001","issue":"2","volume":2014,"language":[{"iso":"eng"}],"publication_status":"published","publication_identifier":{"issn":["17425468"]},"intvolume":" 2014","month":"02","main_file_link":[{"open_access":"1","url":"http://arxiv.org/abs/1403.4516"}],"oa_version":"Submitted Version","abstract":[{"lang":"eng","text":"The purpose of this contribution is to summarize and discuss recent advances regarding the onset of turbulence in shear flows. The absence of a clear-cut instability mechanism, the spatio-temporal intermittent character and extremely long lived transients are some of the major difficulties encountered in these flows and have hindered progress towards understanding the transition process. We will show for the case of pipe flow that concepts from nonlinear dynamics and statistical physics can help to explain the onset of turbulence. In particular, the turbulent structures (puffs) observed close to onset are spatially localized chaotic transients and their lifetimes increase super-exponentially with Reynolds number. At the same time fluctuations of individual turbulent puffs can (although very rarely) lead to the nucleation of new puffs. The competition between these two stochastic processes gives rise to a non-equilibrium phase transition where turbulence changes from a super-transient to a sustained state."}],"department":[{"_id":"BjHo"}],"date_updated":"2022-06-10T10:13:15Z","status":"public","type":"journal_article","article_type":"original","_id":"2232"},{"abstract":[{"text":"Coriolis force effects on shear flows are important in geophysical and astrophysical contexts. We report a study on the linear stability and the transient energy growth of the plane Couette flow with system rotation perpendicular to the shear direction. External rotation causes linear instability. At small rotation rates, the onset of linear instability scales inversely with the rotation rate and the optimal transient growth in the linearly stable region is slightly enhanced ∼Re2. The corresponding optimal initial perturbations are characterized by roll structures inclined in the streamwise direction and are twisted under external rotation. At large rotation rates, the transient growth is significantly inhibited and hence linear stability analysis is a reliable indicator for instability.","lang":"eng"}],"oa_version":"Submitted Version","main_file_link":[{"url":"http://arxiv.org/abs/1312.5095","open_access":"1"}],"scopus_import":1,"intvolume":" 89","month":"01","publication_status":"published","publication_identifier":{"issn":["15393755"]},"language":[{"iso":"eng"}],"volume":89,"issue":"1","_id":"2226","type":"journal_article","status":"public","date_updated":"2021-01-12T06:56:08Z","department":[{"_id":"BjHo"}],"oa":1,"quality_controlled":"1","publisher":"American Institute of Physics","year":"2014","publication":"Physical Review E Statistical Nonlinear and Soft Matter Physics","day":"06","date_created":"2018-12-11T11:56:26Z","doi":"10.1103/PhysRevE.89.013001","date_published":"2014-01-06T00:00:00Z","article_number":"013001","project":[{"name":"Glutamaterge synaptische Übertragung und Plastizität in hippocampalen Mikroschaltkreisen","grant_number":"SFB-TR3-TP10B","_id":"25BDE9A4-B435-11E9-9278-68D0E5697425"}],"citation":{"apa":"Shi, L., Hof, B., & Tilgner, A. (2014). Transient growth of Ekman-Couette flow. Physical Review E Statistical Nonlinear and Soft Matter Physics. American Institute of Physics. https://doi.org/10.1103/PhysRevE.89.013001","ama":"Shi L, Hof B, Tilgner A. Transient growth of Ekman-Couette flow. Physical Review E Statistical Nonlinear and Soft Matter Physics. 2014;89(1). doi:10.1103/PhysRevE.89.013001","ieee":"L. Shi, B. Hof, and A. Tilgner, “Transient growth of Ekman-Couette flow,” Physical Review E Statistical Nonlinear and Soft Matter Physics, vol. 89, no. 1. American Institute of Physics, 2014.","short":"L. Shi, B. Hof, A. Tilgner, Physical Review E Statistical Nonlinear and Soft Matter Physics 89 (2014).","mla":"Shi, Liang, et al. “Transient Growth of Ekman-Couette Flow.” Physical Review E Statistical Nonlinear and Soft Matter Physics, vol. 89, no. 1, 013001, American Institute of Physics, 2014, doi:10.1103/PhysRevE.89.013001.","ista":"Shi L, Hof B, Tilgner A. 2014. Transient growth of Ekman-Couette flow. Physical Review E Statistical Nonlinear and Soft Matter Physics. 89(1), 013001.","chicago":"Shi, Liang, Björn Hof, and Andreas Tilgner. “Transient Growth of Ekman-Couette Flow.” Physical Review E Statistical Nonlinear and Soft Matter Physics. American Institute of Physics, 2014. https://doi.org/10.1103/PhysRevE.89.013001."},"user_id":"4435EBFC-F248-11E8-B48F-1D18A9856A87","author":[{"last_name":"Shi","full_name":"Shi, Liang","first_name":"Liang"},{"last_name":"Hof","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Andreas","full_name":"Tilgner, Andreas","last_name":"Tilgner"}],"publist_id":"4737","title":"Transient growth of Ekman-Couette flow"},{"year":"2013","publication_status":"published","day":"06","language":[{"iso":"eng"}],"publication":"Review of Scientific Instruments","volume":84,"issue":"6","doi":"10.1063/1.4807704","date_published":"2013-06-06T00:00:00Z","date_created":"2018-12-11T11:59:42Z","abstract":[{"lang":"eng","text":"A novel Taylor-Couette system has been constructed for investigations of transitional as well as high Reynolds number turbulent flows in very large aspect ratios. The flexibility of the setup enables studies of a variety of problems regarding hydrodynamic instabilities and turbulence in rotating flows. The inner and outer cylinders and the top and bottom endplates can be rotated independently with rotation rates of up to 30 Hz, thereby covering five orders of magnitude in Reynolds numbers (Re = 101-106). The radius ratio can be easily changed, the highest realized one is η = 0.98 corresponding to an aspect ratio of 260 gap width in the vertical and 300 in the azimuthal direction. For η < 0.98 the aspect ratio can be dynamically changed during measurements and complete transparency in the radial direction over the full length of the cylinders is provided by the usage of a precision glass inner cylinder. The temperatures of both cylinders are controlled independently. Overall this apparatus combines an unmatched variety in geometry, rotation rates, and temperatures, which is provided by a sophisticated high-precision bearing system. Possible applications are accurate studies of the onset of turbulence and spatio-temporal intermittent flow patterns in very large domains, transport processes of turbulence at high Re, the stability of Keplerian flows for different boundary conditions, and studies of baroclinic instabilities."}],"oa_version":"None","scopus_import":1,"quality_controlled":"1","publisher":"American Institute of Physics","month":"06","intvolume":" 84","citation":{"short":"K. Avila, B. Hof, Review of Scientific Instruments 84 (2013).","ieee":"K. Avila and B. Hof, “High-precision Taylor-Couette experiment to study subcritical transitions and the role of boundary conditions and size effects,” Review of Scientific Instruments, vol. 84, no. 6. American Institute of Physics, 2013.","ama":"Avila K, Hof B. High-precision Taylor-Couette experiment to study subcritical transitions and the role of boundary conditions and size effects. Review of Scientific Instruments. 2013;84(6). doi:10.1063/1.4807704","apa":"Avila, K., & Hof, B. (2013). High-precision Taylor-Couette experiment to study subcritical transitions and the role of boundary conditions and size effects. Review of Scientific Instruments. American Institute of Physics. https://doi.org/10.1063/1.4807704","mla":"Avila, Kerstin, and Björn Hof. “High-Precision Taylor-Couette Experiment to Study Subcritical Transitions and the Role of Boundary Conditions and Size Effects.” Review of Scientific Instruments, vol. 84, no. 6, 065106, American Institute of Physics, 2013, doi:10.1063/1.4807704.","ista":"Avila K, Hof B. 2013. High-precision Taylor-Couette experiment to study subcritical transitions and the role of boundary conditions and size effects. Review of Scientific Instruments. 84(6), 065106.","chicago":"Avila, Kerstin, and Björn Hof. “High-Precision Taylor-Couette Experiment to Study Subcritical Transitions and the Role of Boundary Conditions and Size Effects.” Review of Scientific Instruments. American Institute of Physics, 2013. https://doi.org/10.1063/1.4807704."},"date_updated":"2021-01-12T06:59:50Z","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","author":[{"last_name":"Avila","full_name":"Avila, Kerstin","first_name":"Kerstin"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof"}],"publist_id":"4081","department":[{"_id":"BjHo"}],"title":"High-precision Taylor-Couette experiment to study subcritical transitions and the role of boundary conditions and size effects","_id":"2806","article_number":"065106","type":"journal_article","status":"public"},{"project":[{"call_identifier":"FP7","_id":"25152F3A-B435-11E9-9278-68D0E5697425","name":"Decoding the complexity of turbulence at its origin","grant_number":"306589"}],"article_number":"063012","external_id":{"arxiv":["1306.5890"]},"author":[{"first_name":"Marc","last_name":"Avila","full_name":"Avila, Marc"},{"orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof","first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87"}],"publist_id":"4074","title":"Nature of laminar-turbulence intermittency in shear flows","citation":{"mla":"Avila, Marc, and Björn Hof. “Nature of Laminar-Turbulence Intermittency in Shear Flows.” Physical Review E, vol. 87, no. 6, 063012, American Institute of Physics, 2013, doi:10.1103/PhysRevE.87.063012.","apa":"Avila, M., & Hof, B. (2013). Nature of laminar-turbulence intermittency in shear flows. Physical Review E. American Institute of Physics. https://doi.org/10.1103/PhysRevE.87.063012","ama":"Avila M, Hof B. Nature of laminar-turbulence intermittency in shear flows. Physical Review E. 2013;87(6). doi:10.1103/PhysRevE.87.063012","ieee":"M. Avila and B. Hof, “Nature of laminar-turbulence intermittency in shear flows,” Physical Review E, vol. 87, no. 6. American Institute of Physics, 2013.","short":"M. Avila, B. Hof, Physical Review E 87 (2013).","chicago":"Avila, Marc, and Björn Hof. “Nature of Laminar-Turbulence Intermittency in Shear Flows.” Physical Review E. American Institute of Physics, 2013. https://doi.org/10.1103/PhysRevE.87.063012.","ista":"Avila M, Hof B. 2013. Nature of laminar-turbulence intermittency in shear flows. Physical Review E. 87(6), 063012."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","oa":1,"publisher":"American Institute of Physics","quality_controlled":"1","date_created":"2018-12-11T11:59:43Z","date_published":"2013-06-18T00:00:00Z","doi":"10.1103/PhysRevE.87.063012","year":"2013","publication":"Physical Review E","day":"18","type":"journal_article","status":"public","_id":"2811","department":[{"_id":"BjHo"}],"date_updated":"2021-01-12T06:59:53Z","main_file_link":[{"open_access":"1","url":"http://arxiv.org/abs/1306.5890"}],"scopus_import":1,"intvolume":" 87","month":"06","abstract":[{"text":"In pipe, channel, and boundary layer flows turbulence first occurs intermittently in space and time: at moderate Reynolds numbers domains of disordered turbulent motion are separated by quiescent laminar regions. Based on direct numerical simulations of pipe flow we argue here that the spatial intermittency has its origin in a nearest neighbor interaction between turbulent regions. We further show that in this regime turbulent flows are intrinsically intermittent with a well-defined equilibrium turbulent fraction but without ever assuming a steady pattern. This transition scenario is analogous to that found in simple models such as coupled map lattices. The scaling observed implies that laminar intermissions of the turbulent flow will persist to arbitrarily large Reynolds numbers.","lang":"eng"}],"oa_version":"Preprint","ec_funded":1,"volume":87,"issue":"6","publication_status":"published","language":[{"iso":"eng"}]},{"date_updated":"2021-01-12T06:59:54Z","department":[{"_id":"BjHo"}],"_id":"2813","type":"journal_article","status":"public","publication_status":"published","language":[{"iso":"eng"}],"volume":110,"issue":"26","abstract":[{"text":"Turbulence is ubiquitous in nature, yet even for the case of ordinary Newtonian fluids like water, our understanding of this phenomenon is limited. Many liquids of practical importance are more complicated (e.g., blood, polymer melts, paints), however; they exhibit elastic as well as viscous characteristics, and the relation between stress and strain is nonlinear. We demonstrate here for a model system of such complex fluids that at high shear rates, turbulence is not simply modified as previously believed but is suppressed and replaced by a different type of disordered motion, elasto-inertial turbulence. Elasto-inertial turbulence is found to occur at much lower Reynolds numbers than Newtonian turbulence, and the dynamical properties differ significantly. The friction scaling observed coincides with the so-called "maximum drag reduction" asymptote, which is exhibited by a wide range of viscoelastic fluids.","lang":"eng"}],"oa_version":"Submitted Version","pmid":1,"scopus_import":1,"main_file_link":[{"open_access":"1","url":"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3696777/"}],"month":"06","intvolume":" 110","citation":{"mla":"Samanta, Devranjan, et al. “Elasto-Inertial Turbulence.” PNAS, vol. 110, no. 26, National Academy of Sciences, 2013, pp. 10557–62, doi:10.1073/pnas.1219666110.","ieee":"D. Samanta et al., “Elasto-inertial turbulence,” PNAS, vol. 110, no. 26. National Academy of Sciences, pp. 10557–10562, 2013.","short":"D. Samanta, Y. Dubief, M. Holzner, C. Schäfer, A. Morozov, C. Wagner, B. Hof, PNAS 110 (2013) 10557–10562.","apa":"Samanta, D., Dubief, Y., Holzner, M., Schäfer, C., Morozov, A., Wagner, C., & Hof, B. (2013). Elasto-inertial turbulence. PNAS. National Academy of Sciences. https://doi.org/10.1073/pnas.1219666110","ama":"Samanta D, Dubief Y, Holzner M, et al. Elasto-inertial turbulence. PNAS. 2013;110(26):10557-10562. doi:10.1073/pnas.1219666110","chicago":"Samanta, Devranjan, Yves Dubief, Markus Holzner, Christof Schäfer, Alexander Morozov, Christian Wagner, and Björn Hof. “Elasto-Inertial Turbulence.” PNAS. National Academy of Sciences, 2013. https://doi.org/10.1073/pnas.1219666110.","ista":"Samanta D, Dubief Y, Holzner M, Schäfer C, Morozov A, Wagner C, Hof B. 2013. Elasto-inertial turbulence. PNAS. 110(26), 10557–10562."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","author":[{"last_name":"Samanta","full_name":"Samanta, Devranjan","first_name":"Devranjan"},{"first_name":"Yves","full_name":"Dubief, Yves","last_name":"Dubief"},{"first_name":"Markus","full_name":"Holzner, Markus","last_name":"Holzner"},{"last_name":"Schäfer","full_name":"Schäfer, Christof","first_name":"Christof"},{"first_name":"Alexander","last_name":"Morozov","full_name":"Morozov, Alexander"},{"full_name":"Wagner, Christian","last_name":"Wagner","first_name":"Christian"},{"first_name":"Björn","id":"3A374330-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0003-2057-2754","full_name":"Hof, Björn","last_name":"Hof"}],"publist_id":"4073","external_id":{"pmid":["23757498"]},"title":"Elasto-inertial turbulence","year":"2013","day":"25","publication":"PNAS","page":"10557 - 10562","doi":"10.1073/pnas.1219666110","date_published":"2013-06-25T00:00:00Z","date_created":"2018-12-11T11:59:44Z","publisher":"National Academy of Sciences","quality_controlled":"1","oa":1},{"date_updated":"2021-01-12T07:00:00Z","department":[{"_id":"BjHo"}],"_id":"2829","status":"public","type":"journal_article","language":[{"iso":"eng"}],"publication_status":"published","ec_funded":1,"volume":110,"issue":"20","oa_version":"Preprint","abstract":[{"text":"Laminar-turbulent intermittency is intrinsic to the transitional regime of a wide range of fluid flows including pipe, channel, boundary layer, and Couette flow. In the latter turbulent spots can grow and form continuous stripes, yet in the stripe-normal direction they remain interspersed by laminar fluid. We carry out direct numerical simulations in a long narrow domain and observe that individual turbulent stripes are transient. In agreement with recent observations in pipe flow, we find that turbulence becomes sustained at a distinct critical point once the spatial proliferation outweighs the inherent decaying process. By resolving the asymptotic size distributions close to criticality we can for the first time demonstrate scale invariance at the onset of turbulence.","lang":"eng"}],"intvolume":" 110","month":"05","main_file_link":[{"url":"http://arxiv.org/abs/1304.5446","open_access":"1"}],"scopus_import":1,"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","citation":{"chicago":"Shi, Liang, Marc Avila, and Björn Hof. “Scale Invariance at the Onset of Turbulence in Couette Flow.” Physical Review Letters. American Physical Society, 2013. https://doi.org/10.1103/PhysRevLett.110.204502.","ista":"Shi L, Avila M, Hof B. 2013. Scale invariance at the onset of turbulence in couette flow. Physical Review Letters. 110(20), 204502.","mla":"Shi, Liang, et al. “Scale Invariance at the Onset of Turbulence in Couette Flow.” Physical Review Letters, vol. 110, no. 20, 204502, American Physical Society, 2013, doi:10.1103/PhysRevLett.110.204502.","ieee":"L. Shi, M. Avila, and B. Hof, “Scale invariance at the onset of turbulence in couette flow,” Physical Review Letters, vol. 110, no. 20. American Physical Society, 2013.","short":"L. Shi, M. Avila, B. Hof, Physical Review Letters 110 (2013).","ama":"Shi L, Avila M, Hof B. Scale invariance at the onset of turbulence in couette flow. Physical Review Letters. 2013;110(20). doi:10.1103/PhysRevLett.110.204502","apa":"Shi, L., Avila, M., & Hof, B. (2013). Scale invariance at the onset of turbulence in couette flow. Physical Review Letters. American Physical Society. https://doi.org/10.1103/PhysRevLett.110.204502"},"title":"Scale invariance at the onset of turbulence in couette flow","external_id":{"arxiv":["1304.5446"]},"publist_id":"3970","author":[{"id":"374A3F1A-F248-11E8-B48F-1D18A9856A87","first_name":"Liang","full_name":"Shi, Liang","last_name":"Shi"},{"first_name":"Marc","last_name":"Avila","full_name":"Avila, Marc"},{"full_name":"Hof, Björn","orcid":"0000-0003-2057-2754","last_name":"Hof","id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn"}],"article_number":"204502","project":[{"grant_number":"306589","name":"Decoding the complexity of turbulence at its origin","_id":"25152F3A-B435-11E9-9278-68D0E5697425","call_identifier":"FP7"},{"_id":"2511D90C-B435-11E9-9278-68D0E5697425","name":"Astrophysical instability of currents and turbulences","grant_number":"SFB 963 TP A8"}],"publication":"Physical Review Letters","day":"13","year":"2013","date_created":"2018-12-11T11:59:49Z","date_published":"2013-05-13T00:00:00Z","doi":"10.1103/PhysRevLett.110.204502","oa":1,"publisher":"American Physical Society","quality_controlled":"1"},{"publisher":"American Physical Society","quality_controlled":"1","oa":1,"doi":"10.1103/PhysRevLett.110.224502","date_published":"2013-05-29T00:00:00Z","date_created":"2018-12-11T11:59:50Z","year":"2013","day":"29","publication":"Physical Review Letters","project":[{"grant_number":"306589","name":"Decoding the complexity of turbulence at its origin","_id":"25152F3A-B435-11E9-9278-68D0E5697425","call_identifier":"FP7"}],"article_number":"224502","publist_id":"3965","author":[{"first_name":"Marc","full_name":"Avila, Marc","last_name":"Avila"},{"first_name":"Fernando","full_name":"Mellibovsky, Fernando","last_name":"Mellibovsky"},{"first_name":"Nicolas","last_name":"Roland","full_name":"Roland, Nicolas"},{"id":"3A374330-F248-11E8-B48F-1D18A9856A87","first_name":"Björn","last_name":"Hof","full_name":"Hof, Björn","orcid":"0000-0003-2057-2754"}],"external_id":{"arxiv":["1212.0230"]},"title":"Streamwise-localized solutions at the onset of turbulence in pipe flow","citation":{"ista":"Avila M, Mellibovsky F, Roland N, Hof B. 2013. Streamwise-localized solutions at the onset of turbulence in pipe flow. Physical Review Letters. 110(22), 224502.","chicago":"Avila, Marc, Fernando Mellibovsky, Nicolas Roland, and Björn Hof. “Streamwise-Localized Solutions at the Onset of Turbulence in Pipe Flow.” Physical Review Letters. American Physical Society, 2013. https://doi.org/10.1103/PhysRevLett.110.224502.","ama":"Avila M, Mellibovsky F, Roland N, Hof B. Streamwise-localized solutions at the onset of turbulence in pipe flow. Physical Review Letters. 2013;110(22). doi:10.1103/PhysRevLett.110.224502","apa":"Avila, M., Mellibovsky, F., Roland, N., & Hof, B. (2013). Streamwise-localized solutions at the onset of turbulence in pipe flow. Physical Review Letters. American Physical Society. https://doi.org/10.1103/PhysRevLett.110.224502","ieee":"M. Avila, F. Mellibovsky, N. Roland, and B. Hof, “Streamwise-localized solutions at the onset of turbulence in pipe flow,” Physical Review Letters, vol. 110, no. 22. American Physical Society, 2013.","short":"M. Avila, F. Mellibovsky, N. Roland, B. Hof, Physical Review Letters 110 (2013).","mla":"Avila, Marc, et al. “Streamwise-Localized Solutions at the Onset of Turbulence in Pipe Flow.” Physical Review Letters, vol. 110, no. 22, 224502, American Physical Society, 2013, doi:10.1103/PhysRevLett.110.224502."},"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","scopus_import":1,"main_file_link":[{"url":"http://arxiv.org/abs/1212.0230","open_access":"1"}],"month":"05","intvolume":" 110","abstract":[{"lang":"eng","text":"Although the equations governing fluid flow are well known, there are no analytical expressions that describe the complexity of turbulent motion. A recent proposition is that in analogy to low dimensional chaotic systems, turbulence is organized around unstable solutions of the governing equations which provide the building blocks of the disordered dynamics. We report the discovery of periodic solutions which just like intermittent turbulence are spatially localized and show that turbulent transients arise from one such solution branch."}],"oa_version":"Preprint","volume":110,"issue":"22","ec_funded":1,"publication_status":"published","language":[{"iso":"eng"}],"type":"journal_article","status":"public","_id":"2834","department":[{"_id":"BjHo"}],"date_updated":"2021-01-12T07:00:05Z"}]