--- _id: '15045' abstract: - lang: eng text: Coupling of orbital motion to a spin degree of freedom gives rise to various transport phenomena in quantum systems that are beyond the standard paradigms of classical physics. Here, we discuss features of spin-orbit dynamics that can be visualized using a classical model with two coupled angular degrees of freedom. Specifically, we demonstrate classical ‘spin’ filtering through our model and show that the interplay between angular degrees of freedom and dissipation can lead to asymmetric ‘spin’ transport. acknowledgement: "We thank Mikhail Lemeshko and members of his group for many inspiring discussions; Alberto Cappellaro for comments on the manuscript.\r\nOpen access funding provided by Institute of Science and Technology (IST Austria)." article_number: '12' article_processing_charge: Yes (via OA deal) 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: Areg full_name: Ghazaryan, Areg id: 4AF46FD6-F248-11E8-B48F-1D18A9856A87 last_name: Ghazaryan orcid: 0000-0001-9666-3543 - first_name: Artem full_name: Volosniev, Artem id: 37D278BC-F248-11E8-B48F-1D18A9856A87 last_name: Volosniev orcid: 0000-0003-0393-5525 citation: ama: Varshney A, Ghazaryan A, Volosniev A. Classical ‘spin’ filtering with two degrees of freedom and dissipation. Few-Body Systems. 2024;65. doi:10.1007/s00601-024-01880-x apa: Varshney, A., Ghazaryan, A., & Volosniev, A. (2024). Classical ‘spin’ filtering with two degrees of freedom and dissipation. Few-Body Systems. Springer Nature. https://doi.org/10.1007/s00601-024-01880-x chicago: Varshney, Atul, Areg Ghazaryan, and Artem Volosniev. “Classical ‘Spin’ Filtering with Two Degrees of Freedom and Dissipation.” Few-Body Systems. Springer Nature, 2024. https://doi.org/10.1007/s00601-024-01880-x. ieee: A. Varshney, A. Ghazaryan, and A. Volosniev, “Classical ‘spin’ filtering with two degrees of freedom and dissipation,” Few-Body Systems, vol. 65. Springer Nature, 2024. ista: Varshney A, Ghazaryan A, Volosniev A. 2024. Classical ‘spin’ filtering with two degrees of freedom and dissipation. Few-Body Systems. 65, 12. mla: Varshney, Atul, et al. “Classical ‘Spin’ Filtering with Two Degrees of Freedom and Dissipation.” Few-Body Systems, vol. 65, 12, Springer Nature, 2024, doi:10.1007/s00601-024-01880-x. short: A. Varshney, A. Ghazaryan, A. Volosniev, Few-Body Systems 65 (2024). date_created: 2024-03-01T11:39:33Z date_published: 2024-02-17T00:00:00Z date_updated: 2024-03-04T07:08:16Z day: '17' ddc: - '530' department: - _id: MiLe doi: 10.1007/s00601-024-01880-x external_id: arxiv: - '2401.08454' file: - access_level: open_access checksum: c4e08cc7bc756da69b1b36fda7bb92fb content_type: application/pdf creator: dernst date_created: 2024-03-04T07:07:10Z date_updated: 2024-03-04T07:07:10Z file_id: '15049' file_name: 2024_FewBodySys_Varshney.pdf file_size: 436712 relation: main_file success: 1 file_date_updated: 2024-03-04T07:07:10Z has_accepted_license: '1' intvolume: ' 65' keyword: - Atomic and Molecular Physics - and Optics language: - iso: eng license: https://creativecommons.org/licenses/by/4.0/ month: '02' oa: 1 oa_version: Published Version publication: Few-Body Systems publication_identifier: issn: - 1432-5411 publication_status: published publisher: Springer Nature quality_controlled: '1' scopus_import: '1' status: public title: Classical ‘spin’ filtering with two degrees of freedom and dissipation 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: 65 year: '2024' ... --- _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: '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: '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: '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: '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: '17' abstract: - lang: eng text: Creeping flow of polymeric fluid without inertia exhibits elastic instabilities and elastic turbulence accompanied by drag enhancement due to elastic stress produced by flow-stretched polymers. However, in inertia-dominated flow at high Re and low fluid elasticity El, a reduction in turbulent frictional drag is caused by an intricate competition between inertial and elastic stresses. Here we explore the effect of inertia on the stability of viscoelastic flow in a broad range of control parameters El and (Re,Wi). We present the stability diagram of observed flow regimes in Wi-Re coordinates and find that the instabilities' onsets show an unexpectedly nonmonotonic dependence on El. Further, three distinct regions in the diagram are identified based on El. Strikingly, for high-elasticity fluids we discover a complete relaminarization of flow at Reynolds number in the range of 1 to 10, different from a well-known turbulent drag reduction. These counterintuitive effects may be explained by a finite polymer extensibility and a suppression of vorticity at high Wi. Our results call for further theoretical and numerical development to uncover the role of inertial effect on elastic turbulence in a viscoelastic flow. article_number: '103302 ' article_processing_charge: No 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. Drag enhancement and drag reduction in viscoelastic flow. Physical Review Fluids. 2018;3(10). doi:10.1103/PhysRevFluids.3.103302 apa: Varshney, A., & Steinberg, V. (2018). Drag enhancement and drag reduction in viscoelastic flow. Physical Review Fluids. American Physical Society. https://doi.org/10.1103/PhysRevFluids.3.103302 chicago: Varshney, Atul, and Victor Steinberg. “Drag Enhancement and Drag Reduction in Viscoelastic Flow.” Physical Review Fluids. American Physical Society, 2018. https://doi.org/10.1103/PhysRevFluids.3.103302. ieee: A. Varshney and V. Steinberg, “Drag enhancement and drag reduction in viscoelastic flow,” Physical Review Fluids, vol. 3, no. 10. American Physical Society, 2018. ista: Varshney A, Steinberg V. 2018. Drag enhancement and drag reduction in viscoelastic flow. Physical Review Fluids. 3(10), 103302. mla: Varshney, Atul, and Victor Steinberg. “Drag Enhancement and Drag Reduction in Viscoelastic Flow.” Physical Review Fluids, vol. 3, no. 10, 103302, American Physical Society, 2018, doi:10.1103/PhysRevFluids.3.103302. short: A. Varshney, V. Steinberg, Physical Review Fluids 3 (2018). date_created: 2018-12-11T11:44:11Z date_published: 2018-10-15T00:00:00Z date_updated: 2023-09-11T12:59:28Z day: '15' ddc: - '532' department: - _id: BjHo doi: 10.1103/PhysRevFluids.3.103302 ec_funded: 1 external_id: isi: - '000447311500001' file: - access_level: open_access checksum: e1445be33e8165114e96246275600750 content_type: application/pdf creator: system date_created: 2018-12-12T10:10:14Z date_updated: 2020-07-14T12:45:12Z file_id: '4800' file_name: IST-2018-1061-v1+1_PhysRevFluids.3.103302.pdf file_size: 1409040 relation: main_file file_date_updated: 2020-07-14T12:45:12Z has_accepted_license: '1' intvolume: ' 3' isi: 1 issue: '10' language: - iso: eng month: '10' oa: 1 oa_version: Published Version project: - _id: 260C2330-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '754411' name: ISTplus - Postdoctoral Fellowships publication: Physical Review Fluids publication_status: published publisher: American Physical Society publist_id: '8038' pubrep_id: '1061' quality_controlled: '1' scopus_import: '1' status: public title: Drag enhancement and drag reduction in viscoelastic flow type: journal_article user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 volume: 3 year: '2018' ... --- _id: '16' abstract: - lang: eng text: We report quantitative evidence of mixing-layer elastic instability in a viscoelastic fluid flow between two widely spaced obstacles hindering a channel flow at Re 1 and Wi 1. Two mixing layers with nonuniform shear velocity profiles are formed in the region between the obstacles. The mixing-layer instability arises in the vicinity of an inflection point on the shear velocity profile with a steep variation in the elastic stress. The instability results in an intermittent appearance of small vortices in the mixing layers and an amplification of spatiotemporal averaged vorticity in the elastic turbulence regime. The latter is characterized through scaling of friction factor with Wi and both pressure and velocity spectra. Furthermore, the observations reported provide improved understanding of the stability of the mixing layer in a viscoelastic fluid at large elasticity, i.e., Wi 1 and Re 1 and oppose the current view of suppression of vorticity solely by polymer additives. acknowledgement: This work was partially supported by the Israel Science Foundation (ISF; Grant No. 882/15) and the Binational USA-Israel Foundation (BSF; Grant No. 2016145). article_number: '103303' 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. Mixing layer instability and vorticity amplification in a creeping viscoelastic flow. Physical Review Fluids. 2018;3(10). doi:10.1103/PhysRevFluids.3.103303 apa: Varshney, A., & Steinberg, V. (2018). Mixing layer instability and vorticity amplification in a creeping viscoelastic flow. Physical Review Fluids. American Physical Society. https://doi.org/10.1103/PhysRevFluids.3.103303 chicago: Varshney, Atul, and Victor Steinberg. “Mixing Layer Instability and Vorticity Amplification in a Creeping Viscoelastic Flow.” Physical Review Fluids. American Physical Society, 2018. https://doi.org/10.1103/PhysRevFluids.3.103303. ieee: A. Varshney and V. Steinberg, “Mixing layer instability and vorticity amplification in a creeping viscoelastic flow,” Physical Review Fluids, vol. 3, no. 10. American Physical Society, 2018. ista: Varshney A, Steinberg V. 2018. Mixing layer instability and vorticity amplification in a creeping viscoelastic flow. Physical Review Fluids. 3(10), 103303. mla: Varshney, Atul, and Victor Steinberg. “Mixing Layer Instability and Vorticity Amplification in a Creeping Viscoelastic Flow.” Physical Review Fluids, vol. 3, no. 10, 103303, American Physical Society, 2018, doi:10.1103/PhysRevFluids.3.103303. short: A. Varshney, V. Steinberg, Physical Review Fluids 3 (2018). date_created: 2018-12-11T11:44:10Z date_published: 2018-10-16T00:00:00Z date_updated: 2023-09-13T08:57:05Z day: '16' ddc: - '532' department: - _id: BjHo doi: 10.1103/PhysRevFluids.3.103303 ec_funded: 1 external_id: isi: - '000447469200001' file: - access_level: open_access checksum: 7fc0a2322214d1c04debef36d5bf2e8a content_type: application/pdf creator: system date_created: 2018-12-12T10:13:56Z date_updated: 2020-07-14T12:45:04Z file_id: '5043' file_name: IST-2018-1062-v1+1_PhysRevFluids.3.103303.pdf file_size: 1838431 relation: main_file file_date_updated: 2020-07-14T12:45:04Z has_accepted_license: '1' intvolume: ' 3' isi: 1 issue: '10' language: - iso: eng month: '10' oa: 1 oa_version: Submitted Version project: - _id: 260C2330-B435-11E9-9278-68D0E5697425 call_identifier: H2020 grant_number: '754411' name: ISTplus - Postdoctoral Fellowships publication: Physical Review Fluids publication_status: published publisher: American Physical Society publist_id: '8039' pubrep_id: '1062' quality_controlled: '1' scopus_import: '1' status: public title: Mixing layer instability and vorticity amplification in a creeping viscoelastic flow type: journal_article user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 volume: 3 year: '2018' ...