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...

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Detalles Bibliográficos
Autor principal: Mininni, Pablo Daniel
Publicado: 2009
Materias:
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
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15393755_v79_n5_p_Krstulovic
http://hdl.handle.net/20.500.12110/paper_15393755_v79_n5_p_Krstulovic
Aporte de:
Aportado por : Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires .
id paper:paper_15393755_v79_n5_p_Krstulovic
record_format dspace
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
Mininni, Pablo Daniel
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.
author Mininni, Pablo Daniel
author_facet Mininni, Pablo Daniel
author_sort Mininni, Pablo Daniel
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
publishDate 2009
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15393755_v79_n5_p_Krstulovic
http://hdl.handle.net/20.500.12110/paper_15393755_v79_n5_p_Krstulovic
work_keys_str_mv AT mininnipablodaniel cascadesthermalizationandeddyviscosityinhelicalgalerkintruncatedeulerflows
bdutipo_str Repositorios
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