Localized turbulent structures in long pipe flow with minimal set of reflectional symmetry
The laminar-turbulent boundary (edge) separates trajectories approaching a turbulent attractor from those approaching a laminar one, at least for a finite time. To investigate the flow dynamics on the edge we carried out direct numerical simulations of transitional pipe flow (here at Reynolds number...
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2022 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/371814 |
| Acceso en línea: | https://hdl.handle.net/2117/371814 https://dx.doi.org/10.1134/S001546282202001X |
| Access Level: | acceso abierto |
| Palabra clave: | Navier-Stokes equations Computational fluid dynamics Turbulent puffs Edge states Dinàmica de fluids computacional Equacions de Navier-Stokes Àrees temàtiques de la UPC::Física |
| Sumario: | The laminar-turbulent boundary (edge) separates trajectories approaching a turbulent attractor from those approaching a laminar one, at least for a finite time. To investigate the flow dynamics on the edge we carried out direct numerical simulations of transitional pipe flow (here at Reynolds number Re ¿ [2200, 2800]) in a long computational domain. The studied solution has the form of a structure localized in space and traveling downstream. Its qualitative characteristics are similar to the turbulent puffs observed experimentally in the transitional Reynolds number regime. The dynamics within the saddle region of the phase space on the separatrix (hyper-surface in pipe flow) appears to be chaotic. Here, we report such localized solutions on the edge/separatrix for pipe flow and investigate their correlation to turbulent puffs using a minimal set of (artificial) restrictions to the states, i.e., the mirror symmetry, and investigate the resulting flow behavior in this subspace. In contrast to higher symmetry restricted solutions, here detected solutions on the separatrix turn out to be quite as complex as the full state solutions. Worth emphasizing that any solutions found in the subspace are also solutions of the full space and therefore represent physical (symmetric) flow states. |
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