Cascades, thermalization, and eddy viscosity in helical Galerkin truncated Euler flows
The dynamics of the truncated Euler equations with helical initial conditions are studied. Transient energy and helicity cascades leading to Kraichnan helical absolute equilibrium at small scales, including a linear scaling of the relative helicity spectrum are obtained. Strong helicity effects are...
Guardado en:
| Autores principales: | , , , |
|---|---|
| Formato: | JOUR |
| Materias: | |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_15393755_v79_n5_p_Krstulovic |
| Aporte de: |
| id |
todo:paper_15393755_v79_n5_p_Krstulovic |
|---|---|
| record_format |
dspace |
| spelling |
todo:paper_15393755_v79_n5_p_Krstulovic2023-10-03T16:22:25Z Cascades, thermalization, and eddy viscosity in helical Galerkin truncated Euler flows Krstulovic, G. Mininni, P.D. Brachet, M.E. Pouquet, A. Eddy viscosity Euler flows Galerkin Helical flows Helicity Helicity cascades High wave number Ideal flow Initial conditions Linear scaling Navier Stokes Small scale Thermalization Transient energy Transient evolution Wave numbers Dynamics Euler equations Viscosity Navier Stokes equations The dynamics of the truncated Euler equations with helical initial conditions are studied. Transient energy and helicity cascades leading to Kraichnan helical absolute equilibrium at small scales, including a linear scaling of the relative helicity spectrum are obtained. Strong helicity effects are found using initial data concentrated at high wave numbers. Using low-wave-number initial conditions, the results of Cichowlas [Phys. Rev. Lett. 95, 264502 (2005)] are extended to helical flows. Similarities between the turbulent transient evolution of the ideal (time-reversible) system and viscous helical flows are found. Using an argument in the manner of Frisch [Phys. Rev. Lett. 101, 144501 (2008)], the excess of relative helicity found at small scales in the viscous run is related to the thermalization of the ideal flow. The observed differences in the behavior of truncated Euler and (constant viscosity) Navier-Stokes are qualitatively understood using the concept of eddy viscosity. The large scales of truncated Euler equations are then shown to follow quantitatively an effective Navier-Stokes dynamics based on a variable (scale dependent) eddy viscosity. © 2009 The American Physical Society. Fil:Mininni, P.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_15393755_v79_n5_p_Krstulovic |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Eddy viscosity Euler flows Galerkin Helical flows Helicity Helicity cascades High wave number Ideal flow Initial conditions Linear scaling Navier Stokes Small scale Thermalization Transient energy Transient evolution Wave numbers Dynamics Euler equations Viscosity Navier Stokes equations |
| spellingShingle |
Eddy viscosity Euler flows Galerkin Helical flows Helicity Helicity cascades High wave number Ideal flow Initial conditions Linear scaling Navier Stokes Small scale Thermalization Transient energy Transient evolution Wave numbers Dynamics Euler equations Viscosity Navier Stokes equations Krstulovic, G. Mininni, P.D. Brachet, M.E. Pouquet, A. Cascades, thermalization, and eddy viscosity in helical Galerkin truncated Euler flows |
| topic_facet |
Eddy viscosity Euler flows Galerkin Helical flows Helicity Helicity cascades High wave number Ideal flow Initial conditions Linear scaling Navier Stokes Small scale Thermalization Transient energy Transient evolution Wave numbers Dynamics Euler equations Viscosity Navier Stokes equations |
| description |
The dynamics of the truncated Euler equations with helical initial conditions are studied. Transient energy and helicity cascades leading to Kraichnan helical absolute equilibrium at small scales, including a linear scaling of the relative helicity spectrum are obtained. Strong helicity effects are found using initial data concentrated at high wave numbers. Using low-wave-number initial conditions, the results of Cichowlas [Phys. Rev. Lett. 95, 264502 (2005)] are extended to helical flows. Similarities between the turbulent transient evolution of the ideal (time-reversible) system and viscous helical flows are found. Using an argument in the manner of Frisch [Phys. Rev. Lett. 101, 144501 (2008)], the excess of relative helicity found at small scales in the viscous run is related to the thermalization of the ideal flow. The observed differences in the behavior of truncated Euler and (constant viscosity) Navier-Stokes are qualitatively understood using the concept of eddy viscosity. The large scales of truncated Euler equations are then shown to follow quantitatively an effective Navier-Stokes dynamics based on a variable (scale dependent) eddy viscosity. © 2009 The American Physical Society. |
| format |
JOUR |
| author |
Krstulovic, G. Mininni, P.D. Brachet, M.E. Pouquet, A. |
| author_facet |
Krstulovic, G. Mininni, P.D. Brachet, M.E. Pouquet, A. |
| author_sort |
Krstulovic, G. |
| title |
Cascades, thermalization, and eddy viscosity in helical Galerkin truncated Euler flows |
| title_short |
Cascades, thermalization, and eddy viscosity in helical Galerkin truncated Euler flows |
| title_full |
Cascades, thermalization, and eddy viscosity in helical Galerkin truncated Euler flows |
| title_fullStr |
Cascades, thermalization, and eddy viscosity in helical Galerkin truncated Euler flows |
| title_full_unstemmed |
Cascades, thermalization, and eddy viscosity in helical Galerkin truncated Euler flows |
| title_sort |
cascades, thermalization, and eddy viscosity in helical galerkin truncated euler flows |
| url |
http://hdl.handle.net/20.500.12110/paper_15393755_v79_n5_p_Krstulovic |
| work_keys_str_mv |
AT krstulovicg cascadesthermalizationandeddyviscosityinhelicalgalerkintruncatedeulerflows AT mininnipd cascadesthermalizationandeddyviscosityinhelicalgalerkintruncatedeulerflows AT brachetme cascadesthermalizationandeddyviscosityinhelicalgalerkintruncatedeulerflows AT pouqueta cascadesthermalizationandeddyviscosityinhelicalgalerkintruncatedeulerflows |
| _version_ |
1782030717151084544 |