--- _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: '1494' abstract: - lang: eng text: Turbulence is one of the most frequently encountered non-equilibrium phenomena in nature, yet characterizing the transition that gives rise to turbulence in basic shear flows has remained an elusive task. Although, in recent studies, critical points marking the onset of sustained turbulence have been determined for several such flows, the physical nature of the transition could not be fully explained. In extensive experimental and computational studies we show for the example of Couette flow that the onset of turbulence is a second-order phase transition and falls into the directed percolation universality class. Consequently, the complex laminar–turbulent patterns distinctive for the onset of turbulence in shear flows result from short-range interactions of turbulent domains and are characterized by universal critical exponents. More generally, our study demonstrates that even high-dimensional systems far from equilibrium such as turbulence exhibit universality at onset and that here the collective dynamics obeys simple rules. acknowledgement: We thank P. Maier for providing valuable ideas and supporting us in the technical aspects. Discussions with D. Barkley, Y. Duguet, B. Eckhart, N. Goldenfeld, P. Manneville and K. Takeuchi are gratefully acknowledged. We acknowledge the Deutsche Forschungsgemeinschaft (Project No. FOR 1182), and the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement 306589 for financial support. L.S. and B.H. acknowledge research funding by Deutsche Forschungsgemeinschaft (DFG) under Grant No. SFB 963/1 (project A8). Numerical simulations were performed thanks to the CPU time allocations of JUROPA in Juelich Supercomputing Center (project HGU17) and of the Max Planck Computing and Data Facility (Garching, Germany). Excellent technical support from M. Rampp on the hybrid code nsCouette is appreciated. author: - first_name: Grégoire M full_name: Lemoult, Grégoire M id: 4787FE80-F248-11E8-B48F-1D18A9856A87 last_name: Lemoult - first_name: Liang full_name: Shi, Liang id: 374A3F1A-F248-11E8-B48F-1D18A9856A87 last_name: Shi - first_name: Kerstin full_name: Avila, Kerstin last_name: Avila - first_name: Shreyas V full_name: Jalikop, Shreyas V id: 44A1D772-F248-11E8-B48F-1D18A9856A87 last_name: Jalikop - 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: Lemoult GM, Shi L, Avila K, Jalikop SV, Avila M, Hof B. Directed percolation phase transition to sustained turbulence in Couette flow. Nature Physics. 2016;12(3):254-258. doi:10.1038/nphys3675 apa: Lemoult, G. M., Shi, L., Avila, K., Jalikop, S. V., Avila, M., & Hof, B. (2016). Directed percolation phase transition to sustained turbulence in Couette flow. Nature Physics. Nature Publishing Group. https://doi.org/10.1038/nphys3675 chicago: Lemoult, Grégoire M, Liang Shi, Kerstin Avila, Shreyas V Jalikop, Marc Avila, and Björn Hof. “Directed Percolation Phase Transition to Sustained Turbulence in Couette Flow.” Nature Physics. Nature Publishing Group, 2016. https://doi.org/10.1038/nphys3675. ieee: G. M. Lemoult, L. Shi, K. Avila, S. V. Jalikop, M. Avila, and B. Hof, “Directed percolation phase transition to sustained turbulence in Couette flow,” Nature Physics, vol. 12, no. 3. Nature Publishing Group, pp. 254–258, 2016. ista: Lemoult GM, Shi L, Avila K, Jalikop SV, Avila M, Hof B. 2016. Directed percolation phase transition to sustained turbulence in Couette flow. Nature Physics. 12(3), 254–258. mla: Lemoult, Grégoire M., et al. “Directed Percolation Phase Transition to Sustained Turbulence in Couette Flow.” Nature Physics, vol. 12, no. 3, Nature Publishing Group, 2016, pp. 254–58, doi:10.1038/nphys3675. short: G.M. Lemoult, L. Shi, K. Avila, S.V. Jalikop, M. Avila, B. Hof, Nature Physics 12 (2016) 254–258. date_created: 2018-12-11T11:52:21Z date_published: 2016-02-15T00:00:00Z date_updated: 2021-01-12T06:51:08Z day: '15' department: - _id: BjHo doi: 10.1038/nphys3675 ec_funded: 1 intvolume: ' 12' issue: '3' language: - iso: eng month: '02' oa_version: None page: 254 - 258 project: - _id: 25152F3A-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '306589' name: Decoding the complexity of turbulence at its origin - _id: 2511D90C-B435-11E9-9278-68D0E5697425 grant_number: SFB 963 TP A8 name: Astrophysical instability of currents and turbulences publication: Nature Physics publication_status: published publisher: Nature Publishing Group publist_id: '5685' quality_controlled: '1' scopus_import: 1 status: public title: Directed percolation phase transition to sustained turbulence in Couette flow type: journal_article user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 12 year: '2016' ... --- _id: '2030' abstract: - lang: eng text: A hybrid-parallel direct-numerical-simulation method with application to turbulent Taylor-Couette flow is presented. The Navier-Stokes equations are discretized in cylindrical coordinates with the spectral Fourier-Galerkin method in the axial and azimuthal directions, and high-order finite differences in the radial direction. Time is advanced by a second-order, semi-implicit projection scheme, which requires the solution of five Helmholtz/Poisson equations, avoids staggered grids and renders very small slip velocities. Nonlinear terms are evaluated with the pseudospectral method. The code is parallelized using a hybrid MPI-OpenMP strategy, which, compared with a flat MPI parallelization, is simpler to implement, allows to reduce inter-node communications and MPI overhead that become relevant at high processor-core counts, and helps to contain the memory footprint. A strong scaling study shows that the hybrid code maintains scalability up to more than 20,000 processor cores and thus allows to perform simulations at higher resolutions than previously feasible. In particular, it opens up the possibility to simulate turbulent Taylor-Couette flows at Reynolds numbers up to O(105). This enables to probe hydrodynamic turbulence in Keplerian flows in experimentally relevant regimes. author: - first_name: Liang full_name: Shi, Liang id: 374A3F1A-F248-11E8-B48F-1D18A9856A87 last_name: Shi - first_name: Markus full_name: Rampp, Markus last_name: Rampp - 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: Avila, Marc last_name: Avila citation: ama: Shi L, Rampp M, Hof B, Avila M. A hybrid MPI-OpenMP parallel implementation for pseudospectral simulations with application to Taylor-Couette flow. Computers and Fluids. 2015;106(1):1-11. doi:10.1016/j.compfluid.2014.09.021 apa: Shi, L., Rampp, M., Hof, B., & Avila, M. (2015). A hybrid MPI-OpenMP parallel implementation for pseudospectral simulations with application to Taylor-Couette flow. Computers and Fluids. Elsevier. https://doi.org/10.1016/j.compfluid.2014.09.021 chicago: Shi, Liang, Markus Rampp, Björn Hof, and Marc Avila. “A Hybrid MPI-OpenMP Parallel Implementation for Pseudospectral Simulations with Application to Taylor-Couette Flow.” Computers and Fluids. Elsevier, 2015. https://doi.org/10.1016/j.compfluid.2014.09.021. ieee: L. Shi, M. Rampp, B. Hof, and M. Avila, “A hybrid MPI-OpenMP parallel implementation for pseudospectral simulations with application to Taylor-Couette flow,” Computers and Fluids, vol. 106, no. 1. Elsevier, pp. 1–11, 2015. ista: Shi L, Rampp M, Hof B, Avila M. 2015. A hybrid MPI-OpenMP parallel implementation for pseudospectral simulations with application to Taylor-Couette flow. Computers and Fluids. 106(1), 1–11. mla: Shi, Liang, et al. “A Hybrid MPI-OpenMP Parallel Implementation for Pseudospectral Simulations with Application to Taylor-Couette Flow.” Computers and Fluids, vol. 106, no. 1, Elsevier, 2015, pp. 1–11, doi:10.1016/j.compfluid.2014.09.021. short: L. Shi, M. Rampp, B. Hof, M. Avila, Computers and Fluids 106 (2015) 1–11. date_created: 2018-12-11T11:55:18Z date_published: 2015-01-01T00:00:00Z date_updated: 2021-01-12T06:54:51Z day: '01' department: - _id: BjHo doi: 10.1016/j.compfluid.2014.09.021 intvolume: ' 106' issue: '1' language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1311.2481 month: '01' oa: 1 oa_version: Preprint page: 1 - 11 publication: Computers and Fluids publication_status: published publisher: Elsevier publist_id: '5042' quality_controlled: '1' scopus_import: 1 status: public title: A hybrid MPI-OpenMP parallel implementation for pseudospectral simulations with application to Taylor-Couette flow type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 106 year: '2015' ... --- _id: '2829' abstract: - lang: eng text: Laminar-turbulent intermittency is intrinsic to the transitional regime of a wide range of fluid flows including pipe, channel, boundary layer, and Couette flow. In the latter turbulent spots can grow and form continuous stripes, yet in the stripe-normal direction they remain interspersed by laminar fluid. We carry out direct numerical simulations in a long narrow domain and observe that individual turbulent stripes are transient. In agreement with recent observations in pipe flow, we find that turbulence becomes sustained at a distinct critical point once the spatial proliferation outweighs the inherent decaying process. By resolving the asymptotic size distributions close to criticality we can for the first time demonstrate scale invariance at the onset of turbulence. article_number: '204502' author: - 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 - first_name: Björn full_name: Hof, Björn id: 3A374330-F248-11E8-B48F-1D18A9856A87 last_name: Hof orcid: 0000-0003-2057-2754 citation: ama: Shi L, Avila M, Hof B. Scale invariance at the onset of turbulence in couette flow. Physical Review Letters. 2013;110(20). doi:10.1103/PhysRevLett.110.204502 apa: Shi, L., Avila, M., & Hof, B. (2013). Scale invariance at the onset of turbulence in couette flow. Physical Review Letters. American Physical Society. https://doi.org/10.1103/PhysRevLett.110.204502 chicago: Shi, Liang, Marc Avila, and Björn Hof. “Scale Invariance at the Onset of Turbulence in Couette Flow.” Physical Review Letters. American Physical Society, 2013. https://doi.org/10.1103/PhysRevLett.110.204502. ieee: L. Shi, M. Avila, and B. Hof, “Scale invariance at the onset of turbulence in couette flow,” Physical Review Letters, vol. 110, no. 20. American Physical Society, 2013. ista: Shi L, Avila M, Hof B. 2013. Scale invariance at the onset of turbulence in couette flow. Physical Review Letters. 110(20), 204502. mla: Shi, Liang, et al. “Scale Invariance at the Onset of Turbulence in Couette Flow.” Physical Review Letters, vol. 110, no. 20, 204502, American Physical Society, 2013, doi:10.1103/PhysRevLett.110.204502. short: L. Shi, M. Avila, B. Hof, Physical Review Letters 110 (2013). date_created: 2018-12-11T11:59:49Z date_published: 2013-05-13T00:00:00Z date_updated: 2021-01-12T07:00:00Z day: '13' department: - _id: BjHo doi: 10.1103/PhysRevLett.110.204502 ec_funded: 1 external_id: arxiv: - '1304.5446' intvolume: ' 110' issue: '20' language: - iso: eng main_file_link: - open_access: '1' url: http://arxiv.org/abs/1304.5446 month: '05' oa: 1 oa_version: Preprint project: - _id: 25152F3A-B435-11E9-9278-68D0E5697425 call_identifier: FP7 grant_number: '306589' name: Decoding the complexity of turbulence at its origin - _id: 2511D90C-B435-11E9-9278-68D0E5697425 grant_number: SFB 963 TP A8 name: Astrophysical instability of currents and turbulences publication: Physical Review Letters publication_status: published publisher: American Physical Society publist_id: '3970' quality_controlled: '1' scopus_import: 1 status: public title: Scale invariance at the onset of turbulence in couette flow type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 110 year: '2013' ...