--- _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' ...