--- _id: '12165' 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. article_processing_charge: No article_type: original author: - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: 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 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. ieee: B. Hof, “Directed percolation and the transition to turbulence,” Nature Reviews Physics, vol. 5. Springer Nature, pp. 62–72, 2023. ista: Hof B. 2023. Directed percolation and the transition to turbulence. Nature Reviews Physics. 5, 62–72. 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. short: B. Hof, Nature Reviews Physics 5 (2023) 62–72. date_created: 2023-01-12T12:10:18Z date_published: 2023-01-01T00:00:00Z date_updated: 2023-08-01T12:50:48Z day: '01' department: - _id: BjHo doi: 10.1038/s42254-022-00539-y external_id: isi: - '000890148700002' intvolume: ' 5' isi: 1 keyword: - General Physics and Astronomy language: - iso: eng month: '01' oa_version: None page: 62-72 publication: Nature Reviews Physics publication_identifier: eissn: - 2522-5820 publication_status: published publisher: Springer Nature quality_controlled: '1' scopus_import: '1' status: public title: Directed percolation and the transition to turbulence type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 5 year: '2023' ... --- _id: '12105' 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. 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)." article_number: A10 article_processing_charge: Yes (via OA deal) article_type: original author: - first_name: Elena full_name: Marensi, Elena id: 0BE7553A-1004-11EA-B805-18983DDC885E last_name: Marensi - first_name: Gökhan full_name: Yalniz, Gökhan id: 66E74FA2-D8BF-11E9-8249-8DE2E5697425 last_name: Yalniz orcid: 0000-0002-8490-9312 - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 - first_name: Nazmi B full_name: Budanur, Nazmi B id: 3EA1010E-F248-11E8-B48F-1D18A9856A87 last_name: Budanur orcid: 0000-0003-0423-5010 citation: 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. 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. 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. 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. short: E. Marensi, G. Yalniz, B. Hof, N.B. Budanur, Journal of Fluid Mechanics 954 (2023). date_created: 2023-01-08T23:00:53Z date_published: 2023-01-10T00:00:00Z date_updated: 2023-08-01T12:53:23Z day: '10' ddc: - '530' department: - _id: BjHo doi: 10.1017/jfm.2022.1001 external_id: arxiv: - '2101.07516' isi: - '000903336600001' file: - access_level: open_access checksum: 9224f987caefe5dd85a70814d3cce65c content_type: application/pdf creator: dernst date_created: 2023-02-02T12:34:54Z date_updated: 2023-02-02T12:34:54Z file_id: '12489' file_name: 2023_JourFluidMechanics_Marensi.pdf file_size: 1931647 relation: main_file success: 1 file_date_updated: 2023-02-02T12:34:54Z has_accepted_license: '1' intvolume: ' 954' isi: 1 language: - iso: eng month: '01' oa: 1 oa_version: Published Version 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' publication: Journal of Fluid Mechanics publication_identifier: eissn: - 1469-7645 issn: - 0022-1120 publication_status: published publisher: Cambridge University Press quality_controlled: '1' scopus_import: '1' status: public title: Symmetry-reduced dynamic mode decomposition of near-wall turbulence tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 954 year: '2023' ... --- _id: '12681' abstract: - lang: eng 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. 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). article_processing_charge: No article_type: original author: - first_name: Yves full_name: Dubief, Yves last_name: Dubief - first_name: Vincent E. full_name: Terrapon, Vincent E. last_name: Terrapon - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: 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 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 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. 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. ista: Dubief Y, Terrapon VE, Hof B. 2023. Elasto-inertial turbulence. Annual Review of Fluid Mechanics. 55(1), 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. short: Y. Dubief, V.E. Terrapon, B. Hof, Annual Review of Fluid Mechanics 55 (2023) 675–705. date_created: 2023-02-26T23:01:01Z date_published: 2023-01-19T00:00:00Z date_updated: 2023-08-01T13:19:47Z day: '19' ddc: - '530' department: - _id: BjHo doi: 10.1146/annurev-fluid-032822-025933 external_id: isi: - '000915418100026' file: - access_level: open_access checksum: 2666aa3af2a25252d35eb8681d3edff7 content_type: application/pdf creator: dernst date_created: 2023-02-27T09:23:02Z date_updated: 2023-02-27T09:23:02Z file_id: '12690' file_name: 2023_AnnReviewFluidMech_Dubief.pdf file_size: 4036706 relation: main_file success: 1 file_date_updated: 2023-02-27T09:23:02Z has_accepted_license: '1' intvolume: ' 55' isi: 1 issue: '1' language: - iso: eng month: '01' oa: 1 oa_version: Published Version page: 675-705 publication: Annual Review of Fluid Mechanics publication_identifier: eissn: - 1545-4479 issn: - 0066-4189 publication_status: published publisher: Annual Reviews quality_controlled: '1' scopus_import: '1' status: public title: Elasto-inertial turbulence tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 55 year: '2023' ... --- _id: '12682' 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.' 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.).' article_processing_charge: No article_type: original author: - first_name: Marc full_name: Avila, Marc last_name: Avila - first_name: Dwight full_name: Barkley, Dwight last_name: Barkley - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: 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 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 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. 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. ista: Avila M, Barkley D, Hof B. 2023. Transition to turbulence in pipe flow. Annual Review of Fluid Mechanics. 55, 575–602. 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. short: M. Avila, D. Barkley, B. Hof, Annual Review of Fluid Mechanics 55 (2023) 575–602. date_created: 2023-02-26T23:01:01Z date_published: 2023-01-19T00:00:00Z date_updated: 2023-08-01T13:20:30Z day: '19' ddc: - '530' department: - _id: BjHo doi: 10.1146/annurev-fluid-120720-025957 external_id: isi: - '000915418100023' file: - access_level: open_access checksum: f99ef30f76cabc9e5e1946b380c16db4 content_type: application/pdf creator: dernst date_created: 2023-02-27T09:35:52Z date_updated: 2023-02-27T09:35:52Z file_id: '12691' file_name: 2023_AnnReviewFluidMech_Avila.pdf file_size: 4769537 relation: main_file success: 1 file_date_updated: 2023-02-27T09:35:52Z has_accepted_license: '1' intvolume: ' 55' isi: 1 language: - iso: eng month: '01' oa: 1 oa_version: Published Version page: 575-602 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' publication: Annual Review of Fluid Mechanics publication_identifier: issn: - 0066-4189 publication_status: published publisher: Annual Reviews quality_controlled: '1' scopus_import: '1' status: public title: Transition to turbulence in pipe flow tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 55 year: '2023' ... --- _id: '12172' abstract: - lang: eng 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. article_processing_charge: No article_type: original author: - first_name: Bushra full_name: Khatoon, Bushra last_name: Khatoon - first_name: Shoaib full_name: Kamil, Shoaib id: 185a19af-dc7d-11ea-9b2f-8eb2201959e9 last_name: Kamil - first_name: Hitesh full_name: Babu, Hitesh last_name: Babu - first_name: M. full_name: Siraj Alam, M. last_name: Siraj Alam 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' 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.' 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.' 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.' 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.' short: 'B. Khatoon, S. Kamil, H. Babu, M. Siraj Alam, Materials Today: Proceedings 78 (2023) 40–47.' date_created: 2023-01-12T12:11:26Z date_published: 2023-03-20T00:00:00Z date_updated: 2023-08-16T09:08:11Z day: '20' department: - _id: BjHo doi: 10.1016/j.matpr.2022.11.037 intvolume: ' 78' issue: Part 1 keyword: - General Medicine language: - iso: eng month: '03' oa_version: None page: 40-47 publication: 'Materials Today: Proceedings' publication_identifier: issn: - 2214-7853 publication_status: published publisher: Elsevier quality_controlled: '1' scopus_import: '1' status: public title: Experimental analysis of Cascade CSTRs with step and pulse inputs type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 78 year: '2023' ... --- _id: '14341' 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 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. article_processing_charge: No article_type: original author: - first_name: Davide full_name: Scarselli, Davide id: 40315C30-F248-11E8-B48F-1D18A9856A87 last_name: Scarselli orcid: 0000-0001-5227-4271 - first_name: Jose M full_name: Lopez Alonso, Jose M id: 40770848-F248-11E8-B48F-1D18A9856A87 last_name: Lopez Alonso orcid: 0000-0002-0384-2022 - first_name: Atul full_name: Varshney, Atul id: 2A2006B2-F248-11E8-B48F-1D18A9856A87 last_name: Varshney orcid: 0000-0002-3072-5999 - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: 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 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 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. 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. 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. 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. short: D. Scarselli, J.M. Lopez Alonso, A. Varshney, B. Hof, Nature 621 (2023) 71–74. date_created: 2023-09-17T22:01:09Z date_published: 2023-09-07T00:00:00Z date_updated: 2023-09-20T12:10:22Z day: '07' department: - _id: BjHo doi: 10.1038/s41586-023-06399-5 external_id: pmid: - '37673988' intvolume: ' 621' issue: '7977' language: - iso: eng month: '09' oa_version: None page: 71-74 pmid: 1 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' - _id: 238B8092-32DE-11EA-91FC-C7463DDC885E call_identifier: FWF grant_number: I04188 name: Instabilities in pulsating pipe flow of Newtonian and complex fluids publication: Nature publication_identifier: eissn: - 1476-4687 issn: - 0028-0836 publication_status: published publisher: Springer Nature quality_controlled: '1' related_material: link: - description: News on ISTA website relation: press_release url: https://www.ista.ac.at/en/news/pumping-like-the-heart/ scopus_import: '1' status: public title: Turbulence suppression by cardiac-cycle-inspired driving of pipe flow type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 621 year: '2023' ... --- _id: '12726' abstract: - lang: eng 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." acknowledged_ssus: - _id: M-Shop - _id: Bio alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Michael full_name: Riedl, Michael id: 3BE60946-F248-11E8-B48F-1D18A9856A87 last_name: Riedl orcid: 0000-0003-4844-6311 citation: ama: Riedl M. Synchronization in collectively moving active matter. 2023. doi:10.15479/at:ista:12726 apa: Riedl, M. (2023). Synchronization in collectively moving active matter. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:12726 chicago: Riedl, Michael. “Synchronization in Collectively Moving Active Matter.” Institute of Science and Technology Austria, 2023. https://doi.org/10.15479/at:ista:12726. ieee: M. Riedl, “Synchronization in collectively moving active matter,” Institute of Science and Technology Austria, 2023. ista: Riedl M. 2023. Synchronization in collectively moving active matter. Institute of Science and Technology Austria. mla: Riedl, Michael. Synchronization in Collectively Moving Active Matter. Institute of Science and Technology Austria, 2023, doi:10.15479/at:ista:12726. short: M. Riedl, Synchronization in Collectively Moving Active Matter, Institute of Science and Technology Austria, 2023. date_created: 2023-03-15T13:22:13Z date_published: 2023-03-23T00:00:00Z date_updated: 2023-11-30T10:55:13Z day: '23' ddc: - '530' degree_awarded: PhD department: - _id: GradSch - _id: BjHo doi: 10.15479/at:ista:12726 file: - access_level: closed checksum: eba0e19fe57a8c15e7aeab55a845efb7 content_type: application/pdf creator: cchlebak date_created: 2023-03-23T12:49:23Z date_updated: 2023-11-24T11:57:46Z description: the main file is missing the bibliography. See new thesis record 14530 for updated files. file_id: '12745' file_name: Thesis_Riedl_2023.pdf file_size: 63734746 relation: main_file - access_level: closed checksum: 0eb7b650cc8ae843bcec7c8a6109ae03 content_type: application/octet-stream creator: cchlebak date_created: 2023-03-23T12:54:34Z date_updated: 2023-09-24T22:30:03Z embargo_to: open_access file_id: '12746' file_name: Thesis_Riedl_2023_source.rar file_size: 339473651 relation: source_file file_date_updated: 2023-11-24T11:57:46Z has_accepted_license: '1' language: - iso: eng month: '03' oa_version: None page: '260' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '10703' relation: part_of_dissertation status: public - id: '10791' relation: part_of_dissertation status: public - id: '7932' relation: part_of_dissertation status: public - id: '461' relation: part_of_dissertation status: public - id: '14530' relation: new_edition status: public status: public supervisor: - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 title: Synchronization in collectively moving active matter type: dissertation user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9 year: '2023' ... --- _id: '13274' 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. 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.). article_number: '034002' article_processing_charge: No article_type: original author: - first_name: Chaitanya S full_name: Paranjape, Chaitanya S id: 3D85B7C4-F248-11E8-B48F-1D18A9856A87 last_name: Paranjape - first_name: Gökhan full_name: Yalniz, Gökhan id: 66E74FA2-D8BF-11E9-8249-8DE2E5697425 last_name: Yalniz orcid: 0000-0002-8490-9312 - first_name: Yohann full_name: Duguet, Yohann last_name: Duguet - first_name: Nazmi B full_name: Budanur, Nazmi B id: 3EA1010E-F248-11E8-B48F-1D18A9856A87 last_name: Budanur orcid: 0000-0003-0423-5010 - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: 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 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. 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. 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. 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. short: C.S. Paranjape, G. Yalniz, Y. Duguet, N.B. Budanur, B. Hof, Physical Review Letters 131 (2023). date_created: 2023-07-24T09:43:59Z date_published: 2023-07-21T00:00:00Z date_updated: 2023-12-13T11:40:19Z day: '21' department: - _id: GradSch - _id: BjHo doi: 10.1103/physrevlett.131.034002 external_id: arxiv: - '2306.05098' isi: - '001052929900004' intvolume: ' 131' isi: 1 issue: '3' keyword: - General Physics and Astronomy language: - iso: eng main_file_link: - open_access: '1' url: https://doi.org/10.48550/arXiv.2306.05098 month: '07' oa: 1 oa_version: Preprint 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' publication: Physical Review Letters publication_identifier: eissn: - 1079-7114 issn: - 0031-9007 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: Direct path from turbulence to time-periodic solutions type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 131 year: '2023' ... --- _id: '14361' 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. acknowledged_ssus: - _id: Bio - _id: LifeSc - _id: M-Shop 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. article_number: '5633' article_processing_charge: Yes article_type: original author: - first_name: Michael full_name: Riedl, Michael id: 3BE60946-F248-11E8-B48F-1D18A9856A87 last_name: Riedl orcid: 0000-0003-4844-6311 - first_name: Isabelle D full_name: Mayer, Isabelle D id: 61763940-15b2-11ec-abd3-cfaddfbc66b4 last_name: Mayer - first_name: Jack full_name: Merrin, Jack id: 4515C308-F248-11E8-B48F-1D18A9856A87 last_name: Merrin orcid: 0000-0001-5145-4609 - first_name: Michael K full_name: Sixt, Michael K id: 41E9FBEA-F248-11E8-B48F-1D18A9856A87 last_name: Sixt orcid: 0000-0002-6620-9179 - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: 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 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 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. 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. 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. 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). date_created: 2023-09-24T22:01:10Z date_published: 2023-09-13T00:00:00Z date_updated: 2023-12-13T12:29:41Z day: '13' ddc: - '530' - '570' department: - _id: MiSi - _id: NanoFab - _id: BjHo doi: 10.1038/s41467-023-41432-1 ec_funded: 1 external_id: isi: - '001087583700030' pmid: - '37704595' file: - access_level: open_access checksum: 82d2d4ad736cc8493db8ce45cd313f7b content_type: application/pdf creator: dernst date_created: 2023-09-25T08:32:37Z date_updated: 2023-09-25T08:32:37Z file_id: '14366' file_name: 2023_NatureComm_Riedl.pdf file_size: 2317272 relation: main_file success: 1 file_date_updated: 2023-09-25T08:32:37Z has_accepted_license: '1' intvolume: ' 14' isi: 1 language: - iso: eng month: '09' oa: 1 oa_version: Published Version pmid: 1 project: - _id: 25A603A2-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '281556' name: Cytoskeletal force generation and force transduction of migrating leukocytes - _id: 25FE9508-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '724373' name: Cellular navigation along spatial gradients publication: Nature Communications publication_identifier: eissn: - 2041-1723 publication_status: published publisher: Springer Nature quality_controlled: '1' scopus_import: '1' status: public title: Synchronization in collectively moving inanimate and living active matter tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 14 year: '2023' ... --- _id: '14754' 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. 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. article_number: '0112' article_processing_charge: No article_type: original author: - first_name: B. full_name: Wang, B. last_name: Wang - first_name: F. full_name: Mellibovsky, F. last_name: Mellibovsky - first_name: Roger full_name: Ayats López, Roger id: ab77522d-073b-11ed-8aff-e71b39258362 last_name: Ayats López orcid: 0000-0001-6572-0621 - first_name: K. full_name: Deguchi, K. last_name: Deguchi - first_name: A. full_name: Meseguer, A. last_name: Meseguer citation: 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 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. 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. 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. 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. short: B. Wang, F. Mellibovsky, R. Ayats López, K. Deguchi, A. Meseguer, Philosophical Transactions of the Royal Society A 381 (2023). date_created: 2024-01-08T13:11:45Z date_published: 2023-05-01T00:00:00Z date_updated: 2024-01-09T09:15:29Z day: '01' ddc: - '530' department: - _id: BjHo doi: 10.1098/rsta.2022.0112 external_id: pmid: - '36907214' file: - access_level: open_access checksum: 1978d126c0ce2f47c22ac20107cc0106 content_type: application/pdf creator: dernst date_created: 2024-01-09T09:13:53Z date_updated: 2024-01-09T09:13:53Z file_id: '14763' file_name: 2023_PhilTransactionsA_Wang_accepted.pdf file_size: 6421086 relation: main_file success: 1 file_date_updated: 2024-01-09T09:13:53Z has_accepted_license: '1' intvolume: ' 381' issue: '2246' keyword: - General Physics and Astronomy - General Engineering - General Mathematics language: - iso: eng month: '05' oa: 1 oa_version: Submitted Version pmid: 1 publication: Philosophical Transactions of the Royal Society A publication_identifier: eissn: - 1471-2962 issn: - 1364-503X publication_status: published publisher: The Royal Society quality_controlled: '1' scopus_import: '1' status: public title: Mean structure of the supercritical turbulent spiral in Taylor–Couette flow tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 381 year: '2023' ... --- _id: '14466' 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. acknowledgement: E.M. acknowledges funding from the ISTplus fellowship programme. G.Y. and B.H. acknowledge a grant from the Simons Foundation (662960, BH). article_number: A21 article_processing_charge: Yes (via OA deal) article_type: original author: - first_name: Elena full_name: Marensi, Elena id: 0BE7553A-1004-11EA-B805-18983DDC885E last_name: Marensi orcid: 0000-0001-7173-4923 - first_name: Gökhan full_name: Yalniz, Gökhan id: 66E74FA2-D8BF-11E9-8249-8DE2E5697425 last_name: Yalniz orcid: 0000-0002-8490-9312 - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 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 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. 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. 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. 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. short: E. Marensi, G. Yalniz, B. Hof, Journal of Fluid Mechanics 974 (2023). date_created: 2023-10-30T09:32:28Z date_published: 2023-11-10T00:00:00Z date_updated: 2024-02-15T09:06:23Z day: '10' ddc: - '530' department: - _id: GradSch - _id: BjHo doi: 10.1017/jfm.2023.780 external_id: arxiv: - '2212.12406' isi: - '001088363700001' file: - access_level: open_access checksum: 17c64c1fb0d5f73252364bf98b0b9e1a content_type: application/pdf creator: dernst date_created: 2024-02-15T09:05:21Z date_updated: 2024-02-15T09:05:21Z file_id: '14996' file_name: 2023_JourFluidMechanics_Marensi.pdf file_size: 2804641 relation: main_file success: 1 file_date_updated: 2024-02-15T09:05:21Z has_accepted_license: '1' intvolume: ' 974' isi: 1 keyword: - turbulence - transition to turbulence - patterns language: - iso: eng month: '11' oa: 1 oa_version: Published Version 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' publication: Journal of Fluid Mechanics publication_identifier: eissn: - 1469-7645 issn: - 0022-1120 publication_status: published publisher: Cambridge University Press quality_controlled: '1' status: public title: Dynamics and proliferation of turbulent stripes in plane-Poiseuille and plane-Couette flows tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 974 year: '2023' ... --- _id: '14641' acknowledged_ssus: - _id: LifeSc - _id: Bio - _id: CampIT alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Mike full_name: Hennessey-Wesen, Mike id: 3F338C72-F248-11E8-B48F-1D18A9856A87 last_name: Hennessey-Wesen citation: ama: Hennessey-Wesen M. Adaptive mutation in E. coli modulated by luxS. 2023. doi:10.15479/at:ista:14641 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 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. ieee: M. Hennessey-Wesen, “Adaptive mutation in E. coli modulated by luxS,” Institute of Science and Technology Austria, 2023. ista: Hennessey-Wesen M. 2023. Adaptive mutation in E. coli modulated by luxS. Institute of Science and Technology Austria. 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. short: M. Hennessey-Wesen, Adaptive Mutation in E. Coli Modulated by LuxS, Institute of Science and Technology Austria, 2023. date_created: 2023-12-04T13:17:37Z date_published: 2023-11-30T00:00:00Z date_updated: 2024-03-22T13:21:17Z day: '30' ddc: - '570' degree_awarded: PhD department: - _id: GradSch - _id: BjHo doi: 10.15479/at:ista:14641 ec_funded: 1 file: - access_level: closed checksum: 4127c285b34f4bf7fb31ef24f9d14c25 content_type: application/vnd.oasis.opendocument.text creator: mhenness date_created: 2023-12-06T13:13:26Z date_updated: 2023-12-06T13:13:26Z file_id: '14648' file_name: mike_thesis_v06-12-2023.odt file_size: 46405919 relation: source_file - access_level: closed checksum: f5203a61eddaf35235bbc51904d73982 content_type: application/pdf creator: mhenness date_created: 2023-12-06T13:14:15Z date_updated: 2023-12-06T13:14:15Z embargo: 2024-11-30 embargo_to: open_access file_id: '14649' file_name: mike_thesis_v06-12-2023.pdf file_size: 21282155 relation: main_file - access_level: closed checksum: 9f7b4d646f1cfb57e3b9106a8a9cdd9d content_type: application/pdf creator: cchlebak date_created: 2024-03-20T13:19:36Z date_updated: 2024-03-20T13:19:36Z file_id: '15145' file_name: 2023_Hennessey_Michael_Thesis_from_source.pdf file_size: 2930287 relation: other file_date_updated: 2024-03-20T13:19:36Z has_accepted_license: '1' keyword: - microfluidics - miceobiology - mutations - quorum sensing language: - iso: eng month: '11' oa_version: Published Version page: '104' project: - _id: 2564DBCA-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '665385' name: International IST Doctoral Program publication_identifier: issn: - 2663 - 337X publication_status: published publisher: Institute of Science and Technology Austria status: public supervisor: - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 title: Adaptive mutation in E. coli modulated by luxS type: dissertation user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9 year: '2023' ... --- _id: '12134' 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. 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. article_number: 04LT02 article_processing_charge: No article_type: original author: - first_name: Georg full_name: Börner, Georg last_name: Börner - first_name: Malte full_name: Schröder, Malte last_name: Schröder - first_name: Davide full_name: Scarselli, Davide id: 40315C30-F248-11E8-B48F-1D18A9856A87 last_name: Scarselli orcid: 0000-0001-5227-4271 - first_name: Nazmi B full_name: Budanur, Nazmi B id: 3EA1010E-F248-11E8-B48F-1D18A9856A87 last_name: Budanur orcid: 0000-0003-0423-5010 - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 - first_name: Marc full_name: Timme, Marc last_name: Timme 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' 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.' 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.' 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.' 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.' short: 'G. Börner, M. Schröder, D. Scarselli, N.B. Budanur, B. Hof, M. Timme, Journal of Physics: Complexity 3 (2022).' date_created: 2023-01-12T12:03:43Z date_published: 2022-10-25T00:00:00Z date_updated: 2023-02-13T09:15:13Z day: '25' ddc: - '530' department: - _id: BjHo doi: 10.1088/2632-072x/ac99cd file: - access_level: open_access checksum: 35c5c5cb0eb17ea1b5184755daab9fc9 content_type: application/pdf creator: dernst date_created: 2023-01-24T07:24:37Z date_updated: 2023-01-24T07:24:37Z file_id: '12350' file_name: 2022_JourPhysics_Boerner.pdf file_size: 1006106 relation: main_file success: 1 file_date_updated: 2023-01-24T07:24:37Z has_accepted_license: '1' intvolume: ' 3' issue: '4' keyword: - Artificial Intelligence - Computer Networks and Communications - Computer Science Applications - Information Systems language: - iso: eng month: '10' oa: 1 oa_version: Published Version publication: 'Journal of Physics: Complexity' publication_identifier: issn: - 2632-072X publication_status: published publisher: IOP Publishing quality_controlled: '1' scopus_import: '1' status: public title: Explosive transitions in epidemic dynamics tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 3 year: '2022' ... --- _id: '10654' abstract: - lang: eng 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." acknowledged_ssus: - _id: M-Shop 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" article_number: '014502' article_processing_charge: No article_type: original author: - first_name: Lukasz full_name: Klotz, Lukasz id: 2C9AF1C2-F248-11E8-B48F-1D18A9856A87 last_name: Klotz orcid: 0000-0003-1740-7635 - first_name: Grégoire M full_name: Lemoult, Grégoire M id: 4787FE80-F248-11E8-B48F-1D18A9856A87 last_name: Lemoult - first_name: Kerstin full_name: Avila, Kerstin last_name: Avila - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: 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 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. 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. 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. 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. short: L. Klotz, G.M. Lemoult, K. Avila, B. Hof, Physical Review Letters 128 (2022). date_created: 2022-01-23T23:01:28Z date_published: 2022-01-05T00:00:00Z date_updated: 2023-08-02T13:59:19Z day: '05' department: - _id: BjHo doi: 10.1103/PhysRevLett.128.014502 ec_funded: 1 external_id: arxiv: - '2111.14894' isi: - '000748271700010' pmid: - '35061458' intvolume: ' 128' isi: 1 issue: '1' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/2111.14894 month: '01' oa: 1 oa_version: Preprint pmid: 1 project: - _id: 260C2330-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '754411' name: ISTplus - Postdoctoral Fellowships - _id: 25152F3A-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '306589' name: Decoding the complexity of turbulence at its origin - _id: 238598C6-32DE-11EA-91FC-C7463DDC885E grant_number: '662960' name: 'Revisiting the Turbulence Problem Using Statistical Mechanics: Experimental Studies on Transitional and Turbulent Flows' publication: Physical Review Letters publication_identifier: eissn: - 1079-7114 issn: - 0031-9007 publication_status: published publisher: American Physical Society quality_controlled: '1' scopus_import: '1' status: public title: Phase transition to turbulence in spatially extended shear flows type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 128 year: '2022' ... --- _id: '11704' 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. article_number: e0269975 article_processing_charge: No article_type: original author: - first_name: Nazmi B full_name: Budanur, Nazmi B id: 3EA1010E-F248-11E8-B48F-1D18A9856A87 last_name: Budanur orcid: 0000-0003-0423-5010 - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: 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 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. 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. ista: Budanur NB, Hof B. 2022. An autonomous compartmental model for accelerating epidemics. PLoS ONE. 17(7), e0269975. 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. short: N.B. Budanur, B. Hof, PLoS ONE 17 (2022). date_created: 2022-07-31T22:01:48Z date_published: 2022-07-18T00:00:00Z date_updated: 2023-08-03T12:24:22Z day: '18' ddc: - '510' department: - _id: BjHo doi: 10.1371/journal.pone.0269975 external_id: isi: - '000911392100055' file: - access_level: open_access checksum: 1ddd9b91e6dec31ab0e7a8433ca2d452 content_type: application/pdf creator: dernst date_created: 2022-08-01T08:02:38Z date_updated: 2022-08-01T08:02:38Z file_id: '11712' file_name: 2022_PLoSONE_Budanur.pdf file_size: 1421256 relation: main_file success: 1 file_date_updated: 2022-08-01T08:02:38Z has_accepted_license: '1' intvolume: ' 17' isi: 1 issue: '7' language: - iso: eng month: '07' oa: 1 oa_version: Published Version publication: PLoS ONE publication_identifier: eissn: - 1932-6203 publication_status: published publisher: Public Library of Science quality_controlled: '1' related_material: record: - id: '11711' relation: research_data status: public scopus_import: '1' status: public title: An autonomous compartmental model for accelerating epidemics tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 17 year: '2022' ... --- _id: '11711' abstract: - lang: eng text: Codes and data for reproducing the results of N. B. Budanur and B. Hof "An autonomous compartmental model for accelerating epidemics" article_processing_charge: No author: - first_name: Nazmi B full_name: Budanur, Nazmi B id: 3EA1010E-F248-11E8-B48F-1D18A9856A87 last_name: Budanur orcid: 0000-0003-0423-5010 citation: 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 chicago: Budanur, Nazmi B. “Burakbudanur/Autoacc-Public.” Zenodo, 2022. https://doi.org/10.5281/ZENODO.6802720. ieee: N. B. Budanur, “burakbudanur/autoacc-public.” Zenodo, 2022. ista: Budanur NB. 2022. burakbudanur/autoacc-public, Zenodo, 10.5281/ZENODO.6802720. mla: Budanur, Nazmi B. Burakbudanur/Autoacc-Public. Zenodo, 2022, doi:10.5281/ZENODO.6802720. short: N.B. Budanur, (2022). date_created: 2022-08-01T08:06:33Z date_published: 2022-07-06T00:00:00Z date_updated: 2023-08-03T12:24:21Z day: '06' ddc: - '000' department: - _id: BjHo doi: 10.5281/ZENODO.6802720 has_accepted_license: '1' license: https://creativecommons.org/publicdomain/zero/1.0/ main_file_link: - open_access: '1' url: https://doi.org/10.5281/ZENODO.6802720 month: '07' oa: 1 oa_version: Published Version publisher: Zenodo related_material: record: - id: '11704' relation: used_in_publication status: public status: public title: burakbudanur/autoacc-public 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 user_id: 6785fbc1-c503-11eb-8a32-93094b40e1cf year: '2022' ... --- _id: '10820' 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. 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). article_processing_charge: No author: - first_name: Jianxin full_name: Liu, Jianxin last_name: Liu - first_name: Elena full_name: Marensi, Elena id: 0BE7553A-1004-11EA-B805-18983DDC885E last_name: Marensi - first_name: Xuesong full_name: Wu, Xuesong last_name: Wu 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' 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.' 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.' 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.' 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. 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. conference: end_date: 2019-09-06 location: London, United Kingdom name: IUTAM Symposium start_date: 2019-09-02 date_created: 2022-03-04T09:14:34Z date_published: 2022-01-01T00:00:00Z date_updated: 2023-08-03T12:54:59Z day: '01' department: - _id: BjHo doi: 10.1007/978-3-030-67902-6_51 edition: '1' editor: - first_name: Spencer full_name: Sherwin, Spencer last_name: Sherwin - first_name: Peter full_name: Schmid, Peter last_name: Schmid - first_name: Xuesong full_name: Wu, Xuesong last_name: Wu external_id: isi: - '000709087600051' intvolume: ' 38' isi: 1 language: - iso: eng month: '01' oa_version: None page: 587-598 place: Cham publication: IUTAM Laminar-Turbulent Transition publication_identifier: eisbn: - '9783030679026' eissn: - 1875-3493 isbn: - '9783030679019' issn: - 1875-3507 publication_status: published publisher: Springer Nature quality_controlled: '1' scopus_import: '1' series_title: IUTAM Bookseries status: public title: Effects of streaky structures on the instability of supersonic boundary layers type: book_chapter user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 38 year: '2022' ... --- _id: '12137' abstract: - lang: eng 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. 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)." article_number: A21 article_processing_charge: No article_type: original author: - first_name: B. full_name: Wang, B. last_name: Wang - first_name: Roger full_name: Ayats López, Roger id: ab77522d-073b-11ed-8aff-e71b39258362 last_name: Ayats López orcid: 0000-0001-6572-0621 - first_name: K. full_name: Deguchi, K. last_name: Deguchi - first_name: F. full_name: Mellibovsky, F. last_name: Mellibovsky - first_name: A. full_name: Meseguer, A. last_name: Meseguer citation: 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 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 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. 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. 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. 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. short: B. Wang, R. Ayats López, K. Deguchi, F. Mellibovsky, A. Meseguer, Journal of Fluid Mechanics 951 (2022). date_created: 2023-01-12T12:04:17Z date_published: 2022-11-07T00:00:00Z date_updated: 2023-08-04T08:54:16Z day: '07' department: - _id: BjHo doi: 10.1017/jfm.2022.828 external_id: arxiv: - '2207.12990' isi: - '000879446900001' intvolume: ' 951' isi: 1 keyword: - Mechanical Engineering - Mechanics of Materials - Condensed Matter Physics - Applied Mathematics language: - iso: eng main_file_link: - open_access: '1' url: ' https://doi.org/10.48550/arXiv.2207.12990' month: '11' oa: 1 oa_version: Preprint publication: Journal of Fluid Mechanics publication_identifier: eissn: - 1469-7645 issn: - 0022-1120 publication_status: published publisher: Cambridge University Press quality_controlled: '1' scopus_import: '1' status: public title: Self-sustainment of coherent structures in counter-rotating Taylor–Couette flow type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 951 year: '2022' ... --- _id: '12259' 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. ' 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.”' article_number: '093138' article_processing_charge: No article_type: original author: - first_name: George H full_name: Choueiri, George H id: 448BD5BC-F248-11E8-B48F-1D18A9856A87 last_name: Choueiri - first_name: Balachandra full_name: Suri, Balachandra id: 47A5E706-F248-11E8-B48F-1D18A9856A87 last_name: Suri - first_name: Jack full_name: Merrin, Jack id: 4515C308-F248-11E8-B48F-1D18A9856A87 last_name: Merrin orcid: 0000-0001-5145-4609 - first_name: Maksym full_name: Serbyn, Maksym id: 47809E7E-F248-11E8-B48F-1D18A9856A87 last_name: Serbyn orcid: 0000-0002-2399-5827 - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 - first_name: Nazmi B full_name: Budanur, Nazmi B id: 3EA1010E-F248-11E8-B48F-1D18A9856A87 last_name: Budanur orcid: 0000-0003-0423-5010 citation: 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' 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.' 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.' 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.' 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.' short: 'G.H. Choueiri, B. Suri, J. Merrin, M. Serbyn, B. Hof, N.B. Budanur, Chaos: An Interdisciplinary Journal of Nonlinear Science 32 (2022).' date_created: 2023-01-16T09:58:16Z date_published: 2022-09-26T00:00:00Z date_updated: 2023-08-04T09:51:17Z day: '26' ddc: - '530' department: - _id: MaSe - _id: BjHo - _id: NanoFab doi: 10.1063/5.0102904 external_id: arxiv: - '2206.01531' isi: - '000861009600005' file: - access_level: open_access checksum: 17881eff8b21969359a2dd64620120ba content_type: application/pdf creator: dernst date_created: 2023-01-30T09:41:12Z date_updated: 2023-01-30T09:41:12Z file_id: '12445' file_name: 2022_Chaos_Choueiri.pdf file_size: 3209644 relation: main_file success: 1 file_date_updated: 2023-01-30T09:41:12Z has_accepted_license: '1' intvolume: ' 32' isi: 1 issue: '9' keyword: - Applied Mathematics - General Physics and Astronomy - Mathematical Physics - Statistical and Nonlinear Physics language: - iso: eng month: '09' oa: 1 oa_version: Published Version publication: 'Chaos: An Interdisciplinary Journal of Nonlinear Science' publication_identifier: eissn: - 1089-7682 issn: - 1054-1500 publication_status: published publisher: AIP Publishing quality_controlled: '1' scopus_import: '1' status: public title: Crises and chaotic scattering in hydrodynamic pilot-wave experiments tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 32 year: '2022' ... --- _id: '12279' abstract: - lang: eng 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. 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). " article_number: L081301 article_processing_charge: No article_type: original author: - first_name: M. Vijay full_name: Kumar, M. Vijay last_name: Kumar - first_name: Atul full_name: Varshney, Atul id: 2A2006B2-F248-11E8-B48F-1D18A9856A87 last_name: Varshney orcid: 0000-0002-3072-5999 - first_name: Dongyang full_name: Li, Dongyang last_name: Li - first_name: Victor full_name: Steinberg, Victor last_name: Steinberg citation: 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 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 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. 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. 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. short: M.V. Kumar, A. Varshney, D. Li, V. Steinberg, Physical Review Fluids 7 (2022). date_created: 2023-01-16T10:02:40Z date_published: 2022-08-03T00:00:00Z date_updated: 2023-08-04T10:26:40Z day: '03' department: - _id: BjHo doi: 10.1103/physrevfluids.7.l081301 external_id: arxiv: - '2205.12871' isi: - '000836397000001' intvolume: ' 7' isi: 1 issue: '8' keyword: - Fluid Flow and Transfer Processes - Modeling and Simulation - Computational Mechanics language: - iso: eng main_file_link: - open_access: '1' url: ' https://doi.org/10.48550/arXiv.2205.12871' month: '08' oa: 1 oa_version: Preprint publication: Physical Review Fluids publication_identifier: issn: - 2469-990X publication_status: published publisher: American Physical Society quality_controlled: '1' scopus_import: '1' status: public title: Relaminarization of elastic turbulence type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 7 year: '2022' ... --- _id: '12146' 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. ' 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." article_number: '114111' article_processing_charge: No article_type: original author: - first_name: B. full_name: Wang, B. last_name: Wang - first_name: Roger full_name: Ayats López, Roger id: ab77522d-073b-11ed-8aff-e71b39258362 last_name: Ayats López orcid: 0000-0001-6572-0621 - first_name: A. full_name: Meseguer, A. last_name: Meseguer - first_name: F. full_name: Marques, F. last_name: Marques citation: 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 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. 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. 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. 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. short: B. Wang, R. Ayats López, A. Meseguer, F. Marques, Physics of Fluids 34 (2022). date_created: 2023-01-12T12:06:58Z date_published: 2022-11-04T00:00:00Z date_updated: 2023-10-03T11:07:58Z day: '04' department: - _id: BjHo doi: 10.1063/5.0124152 external_id: isi: - '000880665300024' intvolume: ' 34' isi: 1 issue: '11' keyword: - Condensed Matter Physics - Fluid Flow and Transfer Processes - Mechanics of Materials - Computational Mechanics - Mechanical Engineering language: - iso: eng main_file_link: - open_access: '1' url: https://upcommons.upc.edu/handle/2117/385635 month: '11' oa: 1 oa_version: Submitted Version publication: Physics of Fluids publication_identifier: eissn: - 1089-7666 issn: - 1070-6631 publication_status: published publisher: AIP Publishing quality_controlled: '1' scopus_import: '1' status: public title: Phase-locking flows between orthogonally stretching parallel plates type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 34 year: '2022' ... --- _id: '10791' 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 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." article_number: kvac009 article_processing_charge: No article_type: original author: - first_name: Andi H full_name: Hansen, Andi H id: 38853E16-F248-11E8-B48F-1D18A9856A87 last_name: Hansen - first_name: Florian full_name: Pauler, Florian id: 48EA0138-F248-11E8-B48F-1D18A9856A87 last_name: Pauler orcid: 0000-0002-7462-0048 - first_name: Michael full_name: Riedl, Michael id: 3BE60946-F248-11E8-B48F-1D18A9856A87 last_name: Riedl orcid: 0000-0003-4844-6311 - first_name: Carmen full_name: Streicher, Carmen id: 36BCB99C-F248-11E8-B48F-1D18A9856A87 last_name: Streicher - first_name: Anna-Magdalena full_name: Heger, Anna-Magdalena id: 4B76FFD2-F248-11E8-B48F-1D18A9856A87 last_name: Heger - first_name: Susanne full_name: Laukoter, Susanne id: 2D6B7A9A-F248-11E8-B48F-1D18A9856A87 last_name: Laukoter orcid: 0000-0002-7903-3010 - first_name: Christoph M full_name: Sommer, Christoph M id: 4DF26D8C-F248-11E8-B48F-1D18A9856A87 last_name: Sommer orcid: 0000-0003-1216-9105 - first_name: Armel full_name: Nicolas, Armel id: 2A103192-F248-11E8-B48F-1D18A9856A87 last_name: Nicolas - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 - first_name: Li Huei full_name: Tsai, Li Huei last_name: Tsai - first_name: Thomas full_name: Rülicke, Thomas last_name: Rülicke - first_name: Simon full_name: Hippenmeyer, Simon id: 37B36620-F248-11E8-B48F-1D18A9856A87 last_name: Hippenmeyer orcid: 0000-0003-2279-1061 citation: 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 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 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. 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. 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. 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). date_created: 2022-02-25T07:52:11Z date_published: 2022-07-07T00:00:00Z date_updated: 2023-11-30T10:55:12Z day: '07' ddc: - '570' department: - _id: SiHi - _id: BjHo - _id: LifeSc - _id: EM-Fac doi: 10.1093/oons/kvac009 ec_funded: 1 file: - access_level: open_access checksum: 822e76e056c07099d1fb27d1ece5941b content_type: application/pdf creator: dernst date_created: 2023-08-16T08:00:30Z date_updated: 2023-08-16T08:00:30Z file_id: '14061' file_name: 2023_OxfordOpenNeuroscience_Hansen.pdf file_size: 4846551 relation: main_file success: 1 file_date_updated: 2023-08-16T08:00:30Z has_accepted_license: '1' intvolume: ' 1' issue: '1' language: - iso: eng month: '07' oa: 1 oa_version: Published Version project: - _id: 25D61E48-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '618444' name: Molecular Mechanisms of Cerebral Cortex Development - _id: 2625A13E-B435-11E9-9278-68D0E5697425 grant_number: '24812' name: Molecular Mechanisms of Radial Neuronal Migration publication: Oxford Open Neuroscience publication_identifier: eissn: - 2753-149X publication_status: published publisher: Oxford Academic quality_controlled: '1' related_material: record: - id: '12726' relation: dissertation_contains status: public - id: '14530' relation: dissertation_contains status: public status: public title: Tissue-wide effects override cell-intrinsic gene function in radial neuron migration tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 1 year: '2022' ... --- _id: '10703' abstract: - lang: eng 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.' acknowledged_ssus: - _id: LifeSc - _id: Bio - _id: EM-Fac 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. article_processing_charge: No article_type: original author: - first_name: Florian full_name: Gaertner, Florian last_name: Gaertner - first_name: Patricia full_name: Reis-Rodrigues, Patricia last_name: Reis-Rodrigues - first_name: Ingrid full_name: De Vries, Ingrid id: 4C7D837E-F248-11E8-B48F-1D18A9856A87 last_name: De Vries - first_name: Miroslav full_name: Hons, Miroslav id: 4167FE56-F248-11E8-B48F-1D18A9856A87 last_name: Hons orcid: 0000-0002-6625-3348 - first_name: Juan full_name: Aguilera, Juan last_name: Aguilera - first_name: Michael full_name: Riedl, Michael id: 3BE60946-F248-11E8-B48F-1D18A9856A87 last_name: Riedl orcid: 0000-0003-4844-6311 - first_name: Alexander F full_name: Leithner, Alexander F id: 3B1B77E4-F248-11E8-B48F-1D18A9856A87 last_name: Leithner orcid: 0000-0002-1073-744X - first_name: Saren full_name: Tasciyan, Saren id: 4323B49C-F248-11E8-B48F-1D18A9856A87 last_name: Tasciyan orcid: 0000-0003-1671-393X - first_name: Aglaja full_name: Kopf, Aglaja id: 31DAC7B6-F248-11E8-B48F-1D18A9856A87 last_name: Kopf orcid: 0000-0002-2187-6656 - first_name: Jack full_name: Merrin, Jack id: 4515C308-F248-11E8-B48F-1D18A9856A87 last_name: Merrin orcid: 0000-0001-5145-4609 - first_name: Vanessa full_name: Zheden, Vanessa id: 39C5A68A-F248-11E8-B48F-1D18A9856A87 last_name: Zheden orcid: 0000-0002-9438-4783 - first_name: Walter full_name: Kaufmann, Walter id: 3F99E422-F248-11E8-B48F-1D18A9856A87 last_name: Kaufmann orcid: 0000-0001-9735-5315 - first_name: Robert full_name: Hauschild, Robert id: 4E01D6B4-F248-11E8-B48F-1D18A9856A87 last_name: Hauschild orcid: 0000-0001-9843-3522 - first_name: Michael K full_name: Sixt, Michael K id: 41E9FBEA-F248-11E8-B48F-1D18A9856A87 last_name: Sixt orcid: 0000-0002-6620-9179 citation: 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 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 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. 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. 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. 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. 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. date_created: 2022-01-30T23:01:33Z date_published: 2022-01-10T00:00:00Z date_updated: 2024-03-27T23:30:23Z day: '10' ddc: - '570' department: - _id: MiSi - _id: EM-Fac - _id: NanoFab - _id: BjHo doi: 10.1016/j.devcel.2021.11.024 ec_funded: 1 external_id: isi: - '000768933800005' pmid: - '34919802' intvolume: ' 57' isi: 1 issue: '1' language: - iso: eng main_file_link: - open_access: '1' url: https://www.sciencedirect.com/science/article/pii/S1534580721009497 month: '01' oa: 1 oa_version: Published Version page: 47-62.e9 pmid: 1 project: - _id: 260AA4E2-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '747687' name: Mechanical Adaptation of Lamellipodial Actin Networks in Migrating Cells - _id: 25FE9508-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '724373' name: Cellular navigation along spatial gradients publication: Developmental Cell publication_identifier: eissn: - 1878-1551 issn: - 1534-5807 publication_status: published publisher: Cell Press ; Elsevier quality_controlled: '1' related_material: record: - id: '12726' relation: dissertation_contains status: public - id: '14530' relation: dissertation_contains status: public - id: '12401' relation: dissertation_contains status: public scopus_import: '1' status: public title: WASp triggers mechanosensitive actin patches to facilitate immune cell migration in dense tissues tmp: image: /images/cc_by_nc_nd.png legal_code_url: https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode name: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) short: CC BY-NC-ND (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 57 year: '2022' ... --- _id: '8999' abstract: - lang: eng 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. " 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" article_number: '58' article_processing_charge: No article_type: original author: - first_name: Kerstin full_name: Avila, Kerstin id: fcf74381-53e1-11eb-a6dc-b0e2acf78757 last_name: Avila - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: ama: Avila K, Hof B. Second-order phase transition in counter-rotating taylor-couette flow experiment. Entropy. 2021;23(1). 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 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. ieee: K. Avila and B. Hof, “Second-order phase transition in counter-rotating taylor-couette flow experiment,” Entropy, vol. 23, no. 1. MDPI, 2021. 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. short: K. Avila, B. Hof, Entropy 23 (2021). date_created: 2021-01-10T23:01:17Z date_published: 2021-01-01T00:00:00Z date_updated: 2023-08-07T13:31:07Z day: '01' ddc: - '530' department: - _id: BjHo doi: 10.3390/e23010058 external_id: isi: - '000610135400001' pmid: - '33396499' file: - access_level: open_access checksum: 3ba3dd8b7eecff713b72c5e9ba30d626 content_type: application/pdf creator: dernst date_created: 2021-01-11T07:50:32Z date_updated: 2021-01-11T07:50:32Z file_id: '9003' file_name: 2021_Entropy_Avila.pdf file_size: 9456389 relation: main_file success: 1 file_date_updated: 2021-01-11T07:50:32Z has_accepted_license: '1' intvolume: ' 23' isi: 1 issue: '1' language: - iso: eng month: '01' oa: 1 oa_version: Published Version pmid: 1 publication: Entropy publication_identifier: eissn: - 1099-4300 publication_status: published publisher: MDPI quality_controlled: '1' scopus_import: '1' status: public title: Second-order phase transition in counter-rotating taylor-couette flow experiment tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 23 year: '2021' ... --- _id: '9207' abstract: - lang: eng 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." 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." article_number: A24 article_processing_charge: Yes (via OA deal) article_type: original author: - first_name: Lukasz full_name: Klotz, Lukasz id: 2C9AF1C2-F248-11E8-B48F-1D18A9856A87 last_name: Klotz orcid: 0000-0003-1740-7635 - first_name: A. M. full_name: Pavlenko, A. M. last_name: Pavlenko - first_name: J. E. full_name: Wesfreid, J. E. last_name: Wesfreid citation: 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' 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.' 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.' 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.' 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.' short: L. Klotz, A.M. Pavlenko, J.E. Wesfreid, Journal of Fluid Mechanics 912 (2021). date_created: 2021-02-28T23:01:25Z date_published: 2021-02-15T00:00:00Z date_updated: 2023-08-07T13:55:40Z day: '15' ddc: - '530' department: - _id: BjHo doi: 10.1017/jfm.2020.1089 ec_funded: 1 external_id: isi: - '000618034400001' file: - access_level: open_access checksum: b8020d6338667673e34fde0608913dd2 content_type: application/pdf creator: dernst date_created: 2021-03-03T09:49:34Z date_updated: 2021-03-03T09:49:34Z file_id: '9220' file_name: 2021_JourFluidMechanics_Klotz.pdf file_size: 4124471 relation: main_file success: 1 file_date_updated: 2021-03-03T09:49:34Z has_accepted_license: '1' intvolume: ' 912' isi: 1 language: - iso: eng month: '02' oa: 1 oa_version: Published Version project: - _id: 260C2330-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '754411' name: ISTplus - Postdoctoral Fellowships publication: Journal of Fluid Mechanics publication_identifier: eissn: - 1469-7645 issn: - 0022-1120 publication_status: published publisher: Cambridge University Press quality_controlled: '1' scopus_import: '1' status: public title: 'Experimental measurements in plane Couette-Poiseuille flow: Dynamics of the large- and small-scale flow' tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 912 year: '2021' ... --- _id: '9297' 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.' 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." article_number: A65 article_processing_charge: No article_type: original author: - first_name: T. full_name: Liu, T. last_name: Liu - first_name: B. full_name: Semin, B. last_name: Semin - first_name: Lukasz full_name: Klotz, Lukasz id: 2C9AF1C2-F248-11E8-B48F-1D18A9856A87 last_name: Klotz orcid: 0000-0003-1740-7635 - first_name: R. full_name: Godoy-Diana, R. last_name: Godoy-Diana - first_name: J. E. full_name: Wesfreid, J. E. last_name: Wesfreid - first_name: T. full_name: Mullin, T. last_name: Mullin citation: 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 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. 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. 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. short: T. Liu, B. Semin, L. Klotz, R. Godoy-Diana, J.E. Wesfreid, T. Mullin, Journal of Fluid Mechanics 915 (2021). date_created: 2021-03-28T22:01:42Z date_published: 2021-03-17T00:00:00Z date_updated: 2023-08-07T14:30:11Z day: '17' department: - _id: BjHo doi: 10.1017/jfm.2021.89 external_id: arxiv: - '2008.08851' isi: - '000629677500001' intvolume: ' 915' isi: 1 language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/2008.08851 month: '03' oa: 1 oa_version: Preprint publication: Journal of Fluid Mechanics publication_identifier: eissn: - 1469-7645 issn: - 0022-1120 publication_status: published publisher: Cambridge University Press quality_controlled: '1' scopus_import: '1' status: public title: Decay of streaks and rolls in plane Couette-Poiseuille flow type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 915 year: '2021' ... --- _id: '9407' 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.' 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. article_number: '2586' article_processing_charge: No article_type: original author: - first_name: Davide full_name: Scarselli, Davide id: 40315C30-F248-11E8-B48F-1D18A9856A87 last_name: Scarselli orcid: 0000-0001-5227-4271 - first_name: Nazmi B full_name: Budanur, Nazmi B id: 3EA1010E-F248-11E8-B48F-1D18A9856A87 last_name: Budanur orcid: 0000-0003-0423-5010 - first_name: Marc full_name: Timme, Marc last_name: Timme - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: 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. 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. ista: Scarselli D, Budanur NB, Timme M, Hof B. 2021. Discontinuous epidemic transition due to limited testing. Nature Communications. 12(1), 2586. 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. short: D. Scarselli, N.B. Budanur, M. Timme, B. Hof, Nature Communications 12 (2021). date_created: 2021-05-23T22:01:42Z date_published: 2021-05-10T00:00:00Z date_updated: 2023-08-08T13:45:13Z day: '10' ddc: - '570' department: - _id: BjHo doi: 10.1038/s41467-021-22725-9 external_id: isi: - '000687305500044' file: - access_level: open_access checksum: fe26c1b8a7da1ae07a6c03f80ff06ea1 content_type: application/pdf creator: kschuh date_created: 2021-05-25T14:18:40Z date_updated: 2021-05-25T14:18:40Z file_id: '9426' file_name: 2021_NatureCommunications_Scarselli.pdf file_size: 1176573 relation: main_file success: 1 file_date_updated: 2021-05-25T14:18:40Z has_accepted_license: '1' intvolume: ' 12' isi: 1 issue: '1' language: - iso: eng month: '05' oa: 1 oa_version: Published Version publication: Nature Communications publication_identifier: eissn: - '20411723' publication_status: published publisher: Springer Nature quality_controlled: '1' related_material: link: - description: News on IST Homepage relation: press_release url: https://ist.ac.at/en/news/smashing-the-covid-curve/ scopus_import: '1' status: public title: Discontinuous epidemic transition due to limited testing tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 12 year: '2021' ... --- _id: '9467' 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 \U0001D436, 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 \U0001D436≳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 \U0001D436=\U0001D436\U0001D450\U0001D45F(\U0001D445\U0001D452) 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." acknowledgement: The anonymous referees are kindly acknowledged for their useful suggestions andcomments. article_number: A17 article_processing_charge: Yes (via OA deal) article_type: original author: - first_name: Elena full_name: Marensi, Elena id: 0BE7553A-1004-11EA-B805-18983DDC885E last_name: Marensi - first_name: Shuisheng full_name: He, Shuisheng last_name: He - first_name: Ashley P. full_name: Willis, Ashley P. last_name: Willis citation: 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 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 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. 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. 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. 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. short: E. Marensi, S. He, A.P. Willis, Journal of Fluid Mechanics 919 (2021). date_created: 2021-06-06T22:01:30Z date_published: 2021-07-25T00:00:00Z date_updated: 2023-08-08T13:58:41Z day: '25' ddc: - '530' department: - _id: BjHo doi: 10.1017/jfm.2021.371 external_id: arxiv: - '2008.13486' isi: - '000653785000001' file: - access_level: open_access checksum: 867ad077e45c181c2c5ec1311ba27c41 content_type: application/pdf creator: kschuh date_created: 2021-08-03T09:53:28Z date_updated: 2021-08-03T09:53:28Z file_id: '9766' file_name: 2021_JournalFluidMechanics_Marensi.pdf file_size: 4087358 relation: main_file success: 1 file_date_updated: 2021-08-03T09:53:28Z has_accepted_license: '1' intvolume: ' 919' isi: 1 language: - iso: eng month: '07' oa: 1 oa_version: Published Version publication: Journal of Fluid Mechanics publication_identifier: eissn: - '14697645' issn: - '00221120' publication_status: published publisher: Cambridge University Press quality_controlled: '1' scopus_import: '1' status: public title: Suppression of turbulence and travelling waves in a vertical heated pipe tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 919 year: '2021' ... --- _id: '9558' 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" acknowledged_ssus: - _id: ScienComp 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." article_number: '244502' article_processing_charge: No article_type: letter_note author: - first_name: Gökhan full_name: Yalniz, Gökhan id: 66E74FA2-D8BF-11E9-8249-8DE2E5697425 last_name: Yalniz orcid: 0000-0002-8490-9312 - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 - first_name: Nazmi B full_name: Budanur, Nazmi B id: 3EA1010E-F248-11E8-B48F-1D18A9856A87 last_name: Budanur orcid: 0000-0003-0423-5010 citation: 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 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. 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. 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). date_created: 2021-06-16T15:45:36Z date_published: 2021-06-18T00:00:00Z date_updated: 2023-08-08T14:08:36Z day: '18' department: - _id: GradSch - _id: BjHo doi: 10.1103/PhysRevLett.126.244502 external_id: arxiv: - '2007.02584' isi: - '000663310100008' intvolume: ' 126' isi: 1 issue: '24' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/2007.02584 month: '06' oa: 1 oa_version: Preprint 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' publication: Physical Review Letters publication_identifier: eissn: - 1079-7114 issn: - 0031-9007 publication_status: published publisher: American Physical Society quality_controlled: '1' related_material: link: - description: News on IST Homepage relation: press_release url: https://ist.ac.at/en/news/turbulent-flow-simplified/ status: public title: Coarse graining the state space of a turbulent flow using periodic orbits type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 126 year: '2021' ... --- _id: '10203' abstract: - lang: eng 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. 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. article_number: '6063' article_processing_charge: No article_type: original author: - first_name: Luca full_name: Sortino, Luca last_name: Sortino - first_name: Panaiot G. full_name: Zotev, Panaiot G. last_name: Zotev - first_name: Catherine L. full_name: Phillips, Catherine L. last_name: Phillips - first_name: Alistair J. full_name: Brash, Alistair J. last_name: Brash - first_name: Javier full_name: Cambiasso, Javier last_name: Cambiasso - first_name: Elena full_name: Marensi, Elena id: 0BE7553A-1004-11EA-B805-18983DDC885E last_name: Marensi orcid: 0000-0001-7173-4923 - first_name: A. Mark full_name: Fox, A. Mark last_name: Fox - first_name: Stefan A. full_name: Maier, Stefan A. last_name: Maier - first_name: Riccardo full_name: Sapienza, Riccardo last_name: Sapienza - first_name: Alexander I. full_name: Tartakovskii, Alexander I. last_name: Tartakovskii citation: 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 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 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. 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. 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. 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). date_created: 2021-10-31T23:01:30Z date_published: 2021-10-18T00:00:00Z date_updated: 2023-08-14T08:12:12Z day: '18' ddc: - '530' department: - _id: BjHo doi: 10.1038/s41467-021-26262-3 external_id: arxiv: - '2103.16986' isi: - '000708601800015' file: - access_level: open_access checksum: 8580d128389860f732028c521cd5949e content_type: application/pdf creator: cchlebak date_created: 2021-11-03T11:31:24Z date_updated: 2021-11-03T11:31:24Z file_id: '10212' file_name: 2021_NatComm_Sortino.pdf file_size: 1434201 relation: main_file success: 1 file_date_updated: 2021-11-03T11:31:24Z has_accepted_license: '1' intvolume: ' 12' isi: 1 language: - iso: eng month: '10' oa: 1 oa_version: Published Version publication: Nature Communications publication_identifier: eissn: - 2041-1723 publication_status: published publisher: Springer Nature quality_controlled: '1' scopus_import: '1' status: public title: Bright single photon emitters with enhanced quantum efficiency in a two-dimensional semiconductor coupled with dielectric nano-antennas tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 12 year: '2021' ... --- _id: '10299' 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. 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. article_number: e2102350118 article_processing_charge: No article_type: original author: - first_name: George H full_name: Choueiri, George H id: 448BD5BC-F248-11E8-B48F-1D18A9856A87 last_name: Choueiri - first_name: Jose M full_name: Lopez Alonso, Jose M id: 40770848-F248-11E8-B48F-1D18A9856A87 last_name: Lopez Alonso orcid: 0000-0002-0384-2022 - first_name: Atul full_name: Varshney, Atul id: 2A2006B2-F248-11E8-B48F-1D18A9856A87 last_name: Varshney orcid: 0000-0002-3072-5999 - first_name: Sarath full_name: Sankar, Sarath last_name: Sankar - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: 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 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. 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. 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. 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. short: G.H. Choueiri, J.M. Lopez Alonso, A. Varshney, S. Sankar, B. Hof, Proceedings of the National Academy of Sciences 118 (2021). date_created: 2021-11-17T13:24:24Z date_published: 2021-11-03T00:00:00Z date_updated: 2023-08-14T11:50:10Z day: '03' department: - _id: BjHo doi: 10.1073/pnas.2102350118 external_id: arxiv: - '2103.00023' isi: - '000720926900019' pmid: - ' 34732570' intvolume: ' 118' isi: 1 issue: '45' keyword: - multidisciplinary - elastoinertial turbulence - viscoelastic flows - elastic instability - drag reduction language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/2103.00023 month: '11' oa: 1 oa_version: Preprint pmid: 1 project: - _id: 238B8092-32DE-11EA-91FC-C7463DDC885E call_identifier: FWF grant_number: I04188 name: Instabilities in pulsating pipe flow of Newtonian and complex fluids publication: Proceedings of the National Academy of Sciences publication_identifier: eissn: - 1091-6490 issn: - 0027-8424 publication_status: published publisher: National Academy of Sciences quality_controlled: '1' scopus_import: '1' status: public title: Experimental observation of the origin and structure of elastoinertial turbulence type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 118 year: '2021' ... --- _id: '9728' abstract: - lang: eng 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." acknowledged_ssus: - _id: M-Shop alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Nishchal full_name: Agrawal, Nishchal id: 469E6004-F248-11E8-B48F-1D18A9856A87 last_name: Agrawal citation: ama: Agrawal N. Transition to turbulence and drag reduction in particle-laden pipe flows. 2021. doi:10.15479/at:ista:9728 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 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. ieee: N. Agrawal, “Transition to turbulence and drag reduction in particle-laden pipe flows,” Institute of Science and Technology Austria, 2021. ista: Agrawal N. 2021. Transition to turbulence and drag reduction in particle-laden pipe flows. Institute of Science and Technology Austria. 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. short: N. Agrawal, Transition to Turbulence and Drag Reduction in Particle-Laden Pipe Flows, Institute of Science and Technology Austria, 2021. date_created: 2021-07-27T13:40:30Z date_published: 2021-07-29T00:00:00Z date_updated: 2024-02-28T13:14:39Z day: '29' ddc: - '532' degree_awarded: PhD department: - _id: GradSch - _id: BjHo doi: 10.15479/at:ista:9728 file: - access_level: closed checksum: 77436be3563a90435024307b1b5ee7e8 content_type: application/x-zip-compressed creator: nagrawal date_created: 2021-07-28T13:32:02Z date_updated: 2022-07-29T22:30:05Z embargo_to: open_access file_id: '9744' file_name: Transition to Turbulence and Drag Reduction in Particle-Laden Pipe Flows.zip file_size: 22859658 relation: source_file - access_level: open_access checksum: 72a891d7daba85445c29b868c22575ed content_type: application/pdf creator: nagrawal date_created: 2021-07-28T13:32:05Z date_updated: 2022-07-29T22:30:05Z embargo: 2022-07-28 file_id: '9745' file_name: Transition to Turbulence and Drag Reduction in Particle-Laden Pipe Flows.pdf file_size: 18658048 relation: main_file file_date_updated: 2022-07-29T22:30:05Z has_accepted_license: '1' keyword: - Drag Reduction - Transition to Turbulence - Multiphase Flows - particle Laden Flows - Complex Flows - Experiments - Fluid Dynamics language: - iso: eng month: '07' oa: 1 oa_version: Published Version page: '118' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '6189' relation: part_of_dissertation status: public status: public supervisor: - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 title: Transition to turbulence and drag reduction in particle-laden pipe flows tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2021' ... --- _id: '7364' 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. article_number: '100395' article_processing_charge: No article_type: original author: - first_name: Jose M full_name: Lopez Alonso, Jose M id: 40770848-F248-11E8-B48F-1D18A9856A87 last_name: Lopez Alonso orcid: 0000-0002-0384-2022 - first_name: Daniel full_name: Feldmann, Daniel last_name: Feldmann - first_name: Markus full_name: Rampp, Markus last_name: Rampp - first_name: Alberto full_name: Vela-Martín, Alberto last_name: Vela-Martín - first_name: Liang full_name: Shi, Liang id: 374A3F1A-F248-11E8-B48F-1D18A9856A87 last_name: Shi - first_name: Marc full_name: Avila, Marc last_name: Avila citation: 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 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 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. 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. 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. short: J.M. Lopez Alonso, D. Feldmann, M. Rampp, A. Vela-Martín, L. Shi, M. Avila, SoftwareX 11 (2020). date_created: 2020-01-26T23:00:35Z date_published: 2020-01-17T00:00:00Z date_updated: 2023-08-17T14:29:59Z day: '17' ddc: - '000' department: - _id: BjHo doi: 10.1016/j.softx.2019.100395 external_id: arxiv: - '1908.00587' isi: - '000552271200011' file: - access_level: open_access checksum: 2af1a1a3cc33557b345145276f221668 content_type: application/pdf creator: dernst date_created: 2020-01-27T07:32:46Z date_updated: 2020-07-14T12:47:56Z file_id: '7365' file_name: 2020_SoftwareX_Lopez.pdf file_size: 679707 relation: main_file file_date_updated: 2020-07-14T12:47:56Z has_accepted_license: '1' intvolume: ' 11' isi: 1 language: - iso: eng month: '01' oa: 1 oa_version: Published Version publication: SoftwareX publication_identifier: eissn: - '23527110' publication_status: published publisher: Elsevier quality_controlled: '1' scopus_import: '1' status: public title: nsCouette – A high-performance code for direct numerical simulations of turbulent Taylor–Couette flow tmp: image: /images/cc_by_nc_nd.png legal_code_url: https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode name: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) short: CC BY-NC-ND (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 11 year: '2020' ... --- _id: '7534' 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.' article_number: '023903' article_processing_charge: No article_type: original author: - first_name: Nazmi B full_name: Budanur, Nazmi B id: 3EA1010E-F248-11E8-B48F-1D18A9856A87 last_name: Budanur orcid: 0000-0003-0423-5010 - first_name: Elena full_name: Marensi, Elena last_name: Marensi - first_name: Ashley P. full_name: Willis, Ashley P. last_name: Willis - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: 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 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 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. 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. 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. short: N.B. Budanur, E. Marensi, A.P. Willis, B. Hof, Physical Review Fluids 5 (2020). date_created: 2020-02-27T10:26:57Z date_published: 2020-02-21T00:00:00Z date_updated: 2023-08-18T06:44:46Z day: '21' department: - _id: BjHo doi: 10.1103/physrevfluids.5.023903 external_id: arxiv: - '1912.09270' isi: - '000515065100001' intvolume: ' 5' isi: 1 issue: '2' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1912.09270 month: '02' oa: 1 oa_version: Preprint publication: Physical Review Fluids publication_identifier: issn: - 2469-990X publication_status: published publisher: American Physical Society quality_controlled: '1' scopus_import: '1' status: public title: Upper edge of chaos and the energetics of transition in pipe flow type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 5 year: '2020' ... --- _id: '7563' 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." article_number: '033109' article_processing_charge: No article_type: original author: - first_name: Gökhan full_name: Yalniz, Gökhan id: 66E74FA2-D8BF-11E9-8249-8DE2E5697425 last_name: Yalniz orcid: 0000-0002-8490-9312 - first_name: Nazmi B full_name: Budanur, Nazmi B id: 3EA1010E-F248-11E8-B48F-1D18A9856A87 last_name: Budanur orcid: 0000-0003-0423-5010 citation: ama: Yalniz G, Budanur NB. Inferring symbolic dynamics of chaotic flows from persistence. Chaos. 2020;30(3). 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 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. ieee: G. Yalniz and N. B. Budanur, “Inferring symbolic dynamics of chaotic flows from persistence,” Chaos, vol. 30, no. 3. AIP Publishing, 2020. ista: Yalniz G, Budanur NB. 2020. Inferring symbolic dynamics of chaotic flows from persistence. Chaos. 30(3), 033109. 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. short: G. Yalniz, N.B. Budanur, Chaos 30 (2020). date_created: 2020-03-04T08:06:25Z date_published: 2020-03-03T00:00:00Z date_updated: 2023-08-18T06:47:16Z day: '03' department: - _id: BjHo doi: 10.1063/1.5122969 external_id: arxiv: - '1910.04584' isi: - '000519254800002' intvolume: ' 30' isi: 1 issue: '3' language: - iso: eng main_file_link: - open_access: '1' url: https://doi.org/10.1063/1.5122969 month: '03' oa: 1 oa_version: Published Version publication: Chaos publication_identifier: eissn: - 1089-7682 issn: - 1054-1500 publication_status: published publisher: AIP Publishing quality_controlled: '1' scopus_import: '1' status: public title: Inferring symbolic dynamics of chaotic flows from persistence type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 30 year: '2020' ... --- _id: '8043' abstract: - lang: eng 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. 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. article_number: A7 article_processing_charge: Yes (via OA deal) article_type: original author: - first_name: Chaitanya S full_name: Paranjape, Chaitanya S id: 3D85B7C4-F248-11E8-B48F-1D18A9856A87 last_name: Paranjape - first_name: Yohann full_name: Duguet, Yohann last_name: Duguet - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 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 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. 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. ista: Paranjape CS, Duguet Y, Hof B. 2020. Oblique stripe solutions of channel flow. Journal of Fluid Mechanics. 897, A7. 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. short: C.S. Paranjape, Y. Duguet, B. Hof, Journal of Fluid Mechanics 897 (2020). date_created: 2020-06-29T07:59:35Z date_published: 2020-08-25T00:00:00Z date_updated: 2023-08-22T07:48:02Z day: '25' ddc: - '530' department: - _id: BjHo doi: 10.1017/jfm.2020.322 external_id: isi: - '000539132300001' file: - access_level: open_access checksum: 3f487bf6d9286787096306eaa18702e8 content_type: application/pdf creator: cziletti date_created: 2020-06-30T08:37:37Z date_updated: 2020-07-14T12:48:08Z file_id: '8070' file_name: 2020_JournalOfFluidMech_Paranjape.pdf file_size: 767873 relation: main_file file_date_updated: 2020-07-14T12:48:08Z has_accepted_license: '1' intvolume: ' 897' isi: 1 language: - iso: eng month: '08' oa: 1 oa_version: Published Version publication: Journal of Fluid Mechanics publication_identifier: eissn: - '14697645' issn: - '00221120' publication_status: published publisher: Cambridge University Press quality_controlled: '1' scopus_import: '1' status: public title: Oblique stripe solutions of channel flow tmp: image: /images/cc_by_nc_sa.png legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) short: CC BY-NC-SA (4.0) type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 897 year: '2020' ... --- _id: '8634' abstract: - lang: eng 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. 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. article_number: '064501' article_processing_charge: No article_type: original author: - first_name: Balachandra full_name: Suri, Balachandra id: 47A5E706-F248-11E8-B48F-1D18A9856A87 last_name: Suri - first_name: Logan full_name: Kageorge, Logan last_name: Kageorge - first_name: Roman O. full_name: Grigoriev, Roman O. last_name: Grigoriev - first_name: Michael F. full_name: Schatz, Michael F. last_name: Schatz citation: 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 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. 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. 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. short: B. Suri, L. Kageorge, R.O. Grigoriev, M.F. Schatz, Physical Review Letters 125 (2020). date_created: 2020-10-08T17:27:32Z date_published: 2020-08-05T00:00:00Z date_updated: 2023-09-05T12:08:29Z day: '05' department: - _id: BjHo doi: 10.1103/physrevlett.125.064501 ec_funded: 1 external_id: arxiv: - '2008.02367' isi: - '000555785600005' intvolume: ' 125' isi: 1 issue: '6' keyword: - General Physics and Astronomy language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/2008.02367 month: '08' oa: 1 oa_version: Preprint project: - _id: 25681D80-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '291734' name: International IST Postdoc Fellowship Programme publication: Physical Review Letters publication_identifier: eissn: - 1079-7114 issn: - 0031-9007 publication_status: published publisher: American Physical Society quality_controlled: '1' status: public title: Capturing turbulent dynamics and statistics in experiments with unstable periodic orbits type: journal_article user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 volume: 125 year: '2020' ... --- _id: '7932' 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. article_processing_charge: No article_type: original author: - first_name: Duo full_name: Xu, Duo id: 3454D55E-F248-11E8-B48F-1D18A9856A87 last_name: Xu - first_name: Atul full_name: Varshney, Atul id: 2A2006B2-F248-11E8-B48F-1D18A9856A87 last_name: Varshney orcid: 0000-0002-3072-5999 - first_name: Xingyu full_name: Ma, Xingyu id: 34BADBA6-F248-11E8-B48F-1D18A9856A87 last_name: Ma orcid: 0000-0002-0179-9737 - first_name: Baofang full_name: Song, Baofang last_name: Song - first_name: Michael full_name: Riedl, Michael id: 3BE60946-F248-11E8-B48F-1D18A9856A87 last_name: Riedl orcid: 0000-0003-4844-6311 - first_name: Marc full_name: Avila, Marc last_name: Avila - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: 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 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. 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. 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. 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. date_created: 2020-06-07T22:00:51Z date_published: 2020-05-26T00:00:00Z date_updated: 2023-11-30T10:55:13Z day: '26' department: - _id: BjHo doi: 10.1073/pnas.1913716117 ec_funded: 1 external_id: arxiv: - '2005.11190' isi: - '000536797100014' intvolume: ' 117' isi: 1 issue: '21' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/2005.11190 month: '05' oa: 1 oa_version: Preprint page: 11233-11239 project: - _id: 238B8092-32DE-11EA-91FC-C7463DDC885E call_identifier: FWF grant_number: I04188 name: Instabilities in pulsating pipe flow of Newtonian and complex fluids - _id: 260C2330-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '754411' name: ISTplus - Postdoctoral Fellowships publication: Proceedings of the National Academy of Sciences of the United States of America publication_identifier: eissn: - '10916490' issn: - '00278424' publication_status: published publisher: National Academy of Sciences quality_controlled: '1' related_material: link: - description: News on IST Homepage relation: press_release url: https://ist.ac.at/en/news/blood-flows-more-turbulent-than-previously-expected/ record: - id: '12726' relation: dissertation_contains status: public - id: '14530' relation: dissertation_contains status: public scopus_import: '1' status: public title: Nonlinear hydrodynamic instability and turbulence in pulsatile flow type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 117 year: '2020' ... --- _id: '7258' 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. alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Davide full_name: Scarselli, Davide id: 40315C30-F248-11E8-B48F-1D18A9856A87 last_name: Scarselli orcid: 0000-0001-5227-4271 citation: ama: Scarselli D. New approaches to reduce friction in turbulent pipe flow. 2020. doi:10.15479/AT:ISTA:7258 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 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. ieee: D. Scarselli, “New approaches to reduce friction in turbulent pipe flow,” Institute of Science and Technology Austria, 2020. 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. short: D. Scarselli, New Approaches to Reduce Friction in Turbulent Pipe Flow, Institute of Science and Technology Austria, 2020. date_created: 2020-01-12T16:07:26Z date_published: 2020-01-13T00:00:00Z date_updated: 2023-09-15T12:20:08Z day: '13' ddc: - '532' degree_awarded: PhD department: - _id: BjHo doi: 10.15479/AT:ISTA:7258 ec_funded: 1 file: - access_level: closed checksum: 4df1ab24e9896635106adde5a54615bf content_type: application/zip creator: dscarsel date_created: 2020-01-12T15:57:14Z date_updated: 2021-01-13T23:30:05Z embargo_to: open_access file_id: '7259' file_name: 2020_Scarselli_Thesis.zip file_size: 26640830 relation: source_file - access_level: open_access checksum: 48659ab98e3414293c7a721385c2fd1c content_type: application/pdf creator: dscarsel date_created: 2020-01-12T15:56:14Z date_updated: 2021-01-13T23:30:05Z embargo: 2021-01-12 file_id: '7260' file_name: 2020_Scarselli_Thesis.pdf file_size: 8515844 relation: main_file file_date_updated: 2021-01-13T23:30:05Z has_accepted_license: '1' language: - iso: eng month: '01' oa: 1 oa_version: None page: '174' project: - _id: 25152F3A-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '306589' name: Decoding the complexity of turbulence at its origin - _id: 25104D44-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '737549' name: Eliminating turbulence in oil pipelines - _id: 25136C54-B435-11E9-9278-68D0E5697425 grant_number: HO 4393/1-2 name: Experimental studies of the turbulence transition and transport processes in turbulent Taylor-Couette currents publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '6228' relation: part_of_dissertation status: public - id: '6486' relation: part_of_dissertation status: public - id: '461' relation: part_of_dissertation status: public - id: '422' relation: part_of_dissertation status: public status: public supervisor: - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 title: New approaches to reduce friction in turbulent pipe flow type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2020' ... --- _id: '8350' abstract: - lang: eng 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." acknowledged_ssus: - _id: PreCl - _id: Bio - _id: EM-Fac 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." alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Shayan full_name: Shamipour, Shayan id: 40B34FE2-F248-11E8-B48F-1D18A9856A87 last_name: Shamipour citation: ama: Shamipour S. Bulk actin dynamics drive phase segregation in zebrafish oocytes . 2020. doi: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 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. ieee: S. Shamipour, “Bulk actin dynamics drive phase segregation in zebrafish oocytes ,” Institute of Science and Technology Austria, 2020. ista: Shamipour S. 2020. Bulk actin dynamics drive phase segregation in zebrafish oocytes . Institute of Science and Technology Austria. 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. short: S. Shamipour, Bulk Actin Dynamics Drive Phase Segregation in Zebrafish Oocytes , Institute of Science and Technology Austria, 2020. date_created: 2020-09-09T11:12:10Z date_published: 2020-09-09T00:00:00Z date_updated: 2023-09-27T14:16:45Z day: '09' ddc: - '570' degree_awarded: PhD department: - _id: BjHo - _id: CaHe doi: 10.15479/AT:ISTA:8350 file: - access_level: closed checksum: 6e47871c74f85008b9876112eb3fcfa1 content_type: application/vnd.openxmlformats-officedocument.wordprocessingml.document creator: sshamip date_created: 2020-09-09T11:06:27Z date_updated: 2021-09-11T22:30:05Z embargo_to: open_access file_id: '8351' file_name: Shayan-Thesis-Final.docx file_size: 65194814 relation: source_file - access_level: open_access checksum: 1b44c57f04d7e8a6fe41b1c9c55a52a3 content_type: application/pdf creator: sshamip date_created: 2020-09-09T11:06:13Z date_updated: 2021-09-11T22:30:05Z embargo: 2021-09-10 file_id: '8352' file_name: Shayan-Thesis-Final.pdf file_size: 23729605 relation: main_file file_date_updated: 2021-09-11T22:30:05Z has_accepted_license: '1' language: - iso: eng month: '09' oa: 1 oa_version: None page: '107' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria related_material: record: - id: '661' relation: part_of_dissertation status: public - id: '6508' relation: part_of_dissertation status: public - id: '7001' relation: part_of_dissertation status: public - id: '735' relation: part_of_dissertation status: public status: public supervisor: - first_name: Carl-Philipp J full_name: Heisenberg, Carl-Philipp J id: 39427864-F248-11E8-B48F-1D18A9856A87 last_name: Heisenberg orcid: 0000-0002-0912-4566 - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 title: 'Bulk actin dynamics drive phase segregation in zebrafish oocytes ' type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2020' ... --- _id: '5943' 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. article_processing_charge: No article_type: original author: - first_name: Lukasz full_name: Klotz, Lukasz id: 2C9AF1C2-F248-11E8-B48F-1D18A9856A87 last_name: Klotz orcid: 0000-0003-1740-7635 - first_name: Konrad full_name: Gumowski, Konrad last_name: Gumowski - first_name: José Eduardo full_name: Wesfreid, José Eduardo last_name: Wesfreid citation: 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 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. 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. 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. 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. short: L. Klotz, K. Gumowski, J.E. Wesfreid, Journal of Fluid Mechanics 863 (2019) 386–406. date_created: 2019-02-10T22:59:15Z date_published: 2019-03-25T00:00:00Z date_updated: 2023-08-24T14:43:13Z day: '25' department: - _id: BjHo doi: 10.1017/jfm.2018.974 ec_funded: 1 external_id: arxiv: - '1902.07931' isi: - '000526029100016' intvolume: ' 863' isi: 1 language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1902.07931 month: '03' oa: 1 oa_version: Preprint page: 386-406 project: - _id: 260C2330-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '754411' name: ISTplus - Postdoctoral Fellowships publication: Journal of Fluid Mechanics publication_status: published publisher: Cambridge University Press quality_controlled: '1' scopus_import: '1' status: public title: Experiments on a jet in a crossflow in the low-velocity-ratio regime type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 863 year: '2019' ... --- _id: '5878' 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. article_number: '013122' article_processing_charge: No article_type: original author: - first_name: Nazmi B full_name: Budanur, Nazmi B id: 3EA1010E-F248-11E8-B48F-1D18A9856A87 last_name: Budanur orcid: 0000-0003-0423-5010 - first_name: Marc full_name: Fleury, Marc last_name: Fleury citation: 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' 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.' 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.' 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.' short: 'N.B. Budanur, M. Fleury, Chaos: An Interdisciplinary Journal of Nonlinear Science 29 (2019).' date_created: 2019-01-23T08:35:09Z date_published: 2019-01-22T00:00:00Z date_updated: 2023-08-25T10:16:11Z day: '22' department: - _id: BjHo doi: 10.1063/1.5058279 external_id: arxiv: - '1812.09011' isi: - '000457409100028' intvolume: ' 29' isi: 1 issue: '1' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1812.09011 month: '01' oa: 1 oa_version: Preprint publication: 'Chaos: An Interdisciplinary Journal of Nonlinear Science' publication_identifier: eissn: - 1089-7682 issn: - 1054-1500 publication_status: published publisher: AIP Publishing quality_controlled: '1' related_material: link: - relation: erratum url: https://aip.scitation.org/doi/abs/10.1063/1.5097157 scopus_import: '1' status: public title: State space geometry of the chaotic pilot-wave hydrodynamics type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 29 year: '2019' ... --- _id: '6413' 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. article_processing_charge: No article_type: original author: - first_name: Baofang full_name: Song, Baofang last_name: Song - first_name: Carlos full_name: Plana, Carlos last_name: Plana - first_name: Jose M full_name: Lopez Alonso, Jose M id: 40770848-F248-11E8-B48F-1D18A9856A87 last_name: Lopez Alonso orcid: 0000-0002-0384-2022 - first_name: Marc full_name: Avila, Marc last_name: Avila citation: 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 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 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. 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. 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. 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. short: B. Song, C. Plana, J.M. Lopez Alonso, M. Avila, International Journal of Multiphase Flow 117 (2019) 14–24. date_created: 2019-05-13T07:58:35Z date_published: 2019-08-01T00:00:00Z date_updated: 2023-08-25T10:19:55Z day: '01' department: - _id: BjHo doi: 10.1016/j.ijmultiphaseflow.2019.04.027 external_id: arxiv: - '1902.07351' isi: - '000474496000002' intvolume: ' 117' isi: 1 language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1902.07351 month: '08' oa: 1 oa_version: Preprint page: 14-24 publication: International Journal of Multiphase Flow publication_identifier: issn: - '03019322' publication_status: published publisher: Elsevier quality_controlled: '1' scopus_import: '1' status: public title: Phase-field simulation of core-annular pipe flow type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 117 year: '2019' ... --- _id: '6978' abstract: - lang: eng 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. acknowledged_ssus: - _id: ScienComp article_processing_charge: No article_type: original author: - first_name: Nazmi B full_name: Budanur, Nazmi B id: 3EA1010E-F248-11E8-B48F-1D18A9856A87 last_name: Budanur orcid: 0000-0003-0423-5010 - first_name: Akshunna full_name: Dogra, Akshunna last_name: Dogra - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 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 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. 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. ista: Budanur NB, Dogra A, Hof B. 2019. Geometry of transient chaos in streamwise-localized pipe flow turbulence. Physical Review Fluids. 4(10), 102401. 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. short: N.B. Budanur, A. Dogra, B. Hof, Physical Review Fluids 4 (2019) 102401. date_created: 2019-11-04T10:04:01Z date_published: 2019-10-01T00:00:00Z date_updated: 2023-08-30T07:20:03Z day: '01' department: - _id: BjHo doi: 10.1103/PhysRevFluids.4.102401 external_id: arxiv: - '1810.02211' isi: - '000493510400001' intvolume: ' 4' isi: 1 issue: '10' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1810.02211 month: '10' oa: 1 oa_version: Preprint page: '102401' publication: Physical Review Fluids publication_status: published publisher: American Physical Society quality_controlled: '1' scopus_import: '1' status: public title: Geometry of transient chaos in streamwise-localized pipe flow turbulence type: journal_article user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8 volume: 4 year: '2019' ... --- _id: '7397' abstract: - lang: eng 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). article_processing_charge: No article_type: original author: - first_name: Jose M full_name: Lopez Alonso, Jose M id: 40770848-F248-11E8-B48F-1D18A9856A87 last_name: Lopez Alonso orcid: 0000-0002-0384-2022 - first_name: George H full_name: Choueiri, George H id: 448BD5BC-F248-11E8-B48F-1D18A9856A87 last_name: Choueiri - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: 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 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. 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. 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. 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. short: J.M. Lopez Alonso, G.H. Choueiri, B. Hof, Journal of Fluid Mechanics 874 (2019) 699–719. date_created: 2020-01-29T16:05:19Z date_published: 2019-09-10T00:00:00Z date_updated: 2023-09-06T15:36:36Z day: '10' department: - _id: BjHo doi: 10.1017/jfm.2019.486 external_id: arxiv: - '1808.04080' isi: - '000475349900001' intvolume: ' 874' isi: 1 language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1808.04080 month: '09' oa: 1 oa_version: Preprint page: 699-719 publication: Journal of Fluid Mechanics publication_identifier: eissn: - 1469-7645 issn: - 0022-1120 publication_status: published publisher: CUP quality_controlled: '1' scopus_import: '1' status: public title: Dynamics of viscoelastic pipe flow at low Reynolds numbers in the maximum drag reduction limit type: journal_article user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 volume: 874 year: '2019' ... --- _id: '6957' abstract: - lang: eng 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." alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Chaitanya S full_name: Paranjape, Chaitanya S id: 3D85B7C4-F248-11E8-B48F-1D18A9856A87 last_name: Paranjape citation: ama: Paranjape CS. Onset of turbulence in plane Poiseuille flow. 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 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. ieee: C. S. Paranjape, “Onset of turbulence in plane Poiseuille flow,” Institute of Science and Technology Austria, 2019. ista: Paranjape CS. 2019. Onset of turbulence in plane Poiseuille flow. Institute of Science and Technology Austria. mla: Paranjape, Chaitanya S. Onset of Turbulence in Plane Poiseuille Flow. Institute of Science and Technology Austria, 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. date_created: 2019-10-22T12:08:43Z date_published: 2019-10-24T00:00:00Z date_updated: 2023-09-07T12:53:25Z day: '24' ddc: - '532' degree_awarded: PhD department: - _id: BjHo doi: 10.15479/AT:ISTA:6957 file: - access_level: closed checksum: 7ba298ba0ce7e1d11691af6b8eaf0a0a content_type: application/zip creator: cparanjape date_created: 2019-10-23T09:54:43Z date_updated: 2020-07-14T12:47:46Z file_id: '6962' file_name: Chaitanya_Paranjape_source_files_tex_figures.zip file_size: 45828099 relation: source_file - access_level: open_access checksum: 642697618314e31ac31392da7909c2d9 content_type: application/pdf creator: cparanjape date_created: 2019-10-23T10:37:09Z date_updated: 2020-07-14T12:47:46Z file_id: '6963' file_name: Chaitanya_Paranjape_Thesis.pdf file_size: 19504197 relation: main_file file_date_updated: 2020-07-14T12:47:46Z has_accepted_license: '1' keyword: - Instabilities - Turbulence - Nonlinear dynamics language: - iso: eng month: '10' oa: 1 oa_version: Published Version page: '138' publication_identifier: eissn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria status: public supervisor: - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 title: Onset of turbulence in plane Poiseuille flow type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2019' ... --- _id: '7197' abstract: - lang: eng 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. acknowledged_ssus: - _id: LifeSc - _id: Bio article_number: '5744' article_processing_charge: No article_type: original author: - first_name: Paulo R full_name: Dos Santos Caldas, Paulo R id: 38FCDB4C-F248-11E8-B48F-1D18A9856A87 last_name: Dos Santos Caldas orcid: 0000-0001-6730-4461 - first_name: Maria D full_name: Lopez Pelegrin, Maria D id: 319AA9CE-F248-11E8-B48F-1D18A9856A87 last_name: Lopez Pelegrin - first_name: Daniel J. G. full_name: Pearce, Daniel J. G. last_name: Pearce - first_name: Nazmi B full_name: Budanur, Nazmi B id: 3EA1010E-F248-11E8-B48F-1D18A9856A87 last_name: Budanur orcid: 0000-0003-0423-5010 - first_name: Jan full_name: Brugués, Jan last_name: Brugués - first_name: Martin full_name: Loose, Martin id: 462D4284-F248-11E8-B48F-1D18A9856A87 last_name: Loose orcid: 0000-0001-7309-9724 citation: 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 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. 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. 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. 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. 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). date_created: 2019-12-20T12:22:57Z date_published: 2019-12-17T00:00:00Z date_updated: 2023-09-07T13:18:51Z day: '17' ddc: - '570' department: - _id: MaLo - _id: BjHo doi: 10.1038/s41467-019-13702-4 ec_funded: 1 external_id: isi: - '000503009300001' file: - access_level: open_access checksum: a1b44b427ba341383197790d0e8789fa content_type: application/pdf creator: dernst date_created: 2019-12-23T07:34:56Z date_updated: 2020-07-14T12:47:53Z file_id: '7208' file_name: 2019_NatureComm_Caldas.pdf file_size: 8488733 relation: main_file file_date_updated: 2020-07-14T12:47:53Z has_accepted_license: '1' intvolume: ' 10' isi: 1 language: - iso: eng month: '12' oa: 1 oa_version: Published Version project: - _id: 2595697A-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '679239' name: Self-Organization of the Bacterial Cell - _id: 260D98C8-B435-11E9-9278-68D0E5697425 name: Reconstitution of Bacterial Cell Division Using Purified Components publication: Nature Communications publication_identifier: issn: - 2041-1723 publication_status: published publisher: Springer Nature quality_controlled: '1' related_material: record: - id: '8358' relation: dissertation_contains status: public scopus_import: '1' status: public title: Cooperative ordering of treadmilling filaments in cytoskeletal networks of FtsZ and its crosslinker ZapA tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 volume: 10 year: '2019' ... --- _id: '6069' abstract: - lang: eng 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. article_number: '937' article_processing_charge: No author: - first_name: Jonathan full_name: Mayzel, Jonathan last_name: Mayzel - first_name: Victor full_name: Steinberg, Victor last_name: Steinberg - first_name: Atul full_name: Varshney, Atul id: 2A2006B2-F248-11E8-B48F-1D18A9856A87 last_name: Varshney orcid: 0000-0002-3072-5999 citation: 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 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 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. ieee: J. Mayzel, V. Steinberg, and A. Varshney, “Stokes flow analogous to viscous electron current in graphene,” Nature Communications, vol. 10. Springer Nature, 2019. ista: Mayzel J, Steinberg V, Varshney A. 2019. Stokes flow analogous to viscous electron current in graphene. Nature Communications. 10, 937. 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. short: J. Mayzel, V. Steinberg, A. Varshney, Nature Communications 10 (2019). date_created: 2019-03-05T13:18:30Z date_published: 2019-02-26T00:00:00Z date_updated: 2023-09-08T11:39:02Z day: '26' ddc: - '530' - '532' department: - _id: BjHo doi: 10.1038/s41467-019-08916-5 ec_funded: 1 external_id: isi: - '000459704600001' file: - access_level: open_access checksum: 61192fc49e0d44907c2a4fe384e4b97f content_type: application/pdf creator: dernst date_created: 2019-03-05T13:33:04Z date_updated: 2020-07-14T12:47:18Z file_id: '6070' file_name: 2019_NatureComm_Mayzel.pdf file_size: 2646391 relation: main_file file_date_updated: 2020-07-14T12:47:18Z has_accepted_license: '1' intvolume: ' 10' isi: 1 language: - iso: eng month: '02' oa: 1 oa_version: Published Version project: - _id: 260C2330-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '754411' name: ISTplus - Postdoctoral Fellowships publication: Nature Communications publication_identifier: issn: - 2041-1723 publication_status: published publisher: Springer Nature quality_controlled: '1' scopus_import: '1' status: public title: Stokes flow analogous to viscous electron current in graphene tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 volume: 10 year: '2019' ... --- _id: '6014' abstract: - lang: eng 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. article_number: '652' article_processing_charge: No article_type: original author: - first_name: Atul full_name: Varshney, Atul id: 2A2006B2-F248-11E8-B48F-1D18A9856A87 last_name: Varshney orcid: 0000-0002-3072-5999 - first_name: Victor full_name: Steinberg, Victor last_name: Steinberg citation: ama: Varshney A, Steinberg V. Elastic alfven waves in elastic turbulence. Nature Communications. 2019;10. 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 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. ieee: A. Varshney and V. Steinberg, “Elastic alfven waves in elastic turbulence,” Nature Communications, vol. 10. Springer Nature, 2019. 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. short: A. Varshney, V. Steinberg, Nature Communications 10 (2019). date_created: 2019-02-15T07:10:46Z date_published: 2019-02-08T00:00:00Z date_updated: 2023-09-08T11:39:54Z day: '08' ddc: - '530' department: - _id: BjHo doi: 10.1038/s41467-019-08551-0 ec_funded: 1 external_id: arxiv: - '1902.03763' isi: - '000458175300001' file: - access_level: open_access checksum: d3acf07eaad95ec040d8e8565fc9ac37 content_type: application/pdf creator: dernst date_created: 2019-02-15T07:15:00Z date_updated: 2020-07-14T12:47:17Z file_id: '6015' file_name: 2019_NatureComm_Varshney.pdf file_size: 1331490 relation: main_file file_date_updated: 2020-07-14T12:47:17Z has_accepted_license: '1' intvolume: ' 10' isi: 1 language: - iso: eng month: '02' oa: 1 oa_version: Published Version project: - _id: 260C2330-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '754411' name: ISTplus - Postdoctoral Fellowships publication: Nature Communications publication_identifier: issn: - 2041-1723 publication_status: published publisher: Springer Nature quality_controlled: '1' scopus_import: '1' status: public title: Elastic alfven waves in elastic turbulence tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 volume: 10 year: '2019' ... --- _id: '6779' abstract: - lang: eng 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." article_number: '013112' article_processing_charge: No article_type: original author: - first_name: Balachandra full_name: Suri, Balachandra id: 47A5E706-F248-11E8-B48F-1D18A9856A87 last_name: Suri - first_name: Ravi Kumar full_name: Pallantla, Ravi Kumar last_name: Pallantla - first_name: Michael F. full_name: Schatz, Michael F. last_name: Schatz - first_name: Roman O. full_name: Grigoriev, Roman O. last_name: Grigoriev citation: 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 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. 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. 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. short: B. Suri, R.K. Pallantla, M.F. Schatz, R.O. Grigoriev, Physical Review E 100 (2019). date_created: 2019-08-09T09:40:41Z date_published: 2019-07-25T00:00:00Z date_updated: 2024-02-28T13:13:00Z day: '25' ddc: - '532' department: - _id: BjHo doi: 10.1103/physreve.100.013112 ec_funded: 1 external_id: arxiv: - '1907.05860' isi: - '000477911800012' intvolume: ' 100' isi: 1 issue: '1' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1907.05860 month: '07' oa: 1 oa_version: Preprint project: - _id: 25681D80-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '291734' name: International IST Postdoc Fellowship Programme publication: Physical Review E publication_identifier: eissn: - 2470-0053 issn: - 2470-0045 publication_status: published publisher: American Physical Society quality_controlled: '1' scopus_import: '1' status: public title: Heteroclinic and homoclinic connections in a Kolmogorov-like flow type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 100 year: '2019' ...