Artículo
Cascades, thermalization, and eddy viscosity in helical Galerkin truncated Euler flows
Fecha de publicación:
12/2009
Editorial:
American Physical Society
Revista:
Physical Review E: Statistical, Nonlinear and Soft Matter Physics
ISSN:
1539-3755
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
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.
Palabras clave:
Turbulence
,
Statistical Mechanics
,
Helicity
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Articulos(IFIBA)
Articulos de INST.DE FISICA DE BUENOS AIRES
Articulos de INST.DE FISICA DE BUENOS AIRES
Citación
Krstulovic, G.; Mininni, Pablo Daniel; Brachet, M. E.; Pouquet, A.; Cascades, thermalization, and eddy viscosity in helical Galerkin truncated Euler flows; American Physical Society; Physical Review E: Statistical, Nonlinear and Soft Matter Physics; 79; 5; 12-2009; 563041-563045
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