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Accueil > Actualités > Séminaires > Séminaires 2014

Mardi 9 septembre 2014 à 11h00 en salle K118

Professor Peter Davidson, dept of engineering, University Cambridge

Titre/Title :
Decay laws in homogeneous turbulence

Contact :
Joel Sommeria

Résumé/Abstract :
Almost any freely-evolving homogeneous turbulent system possesses one or
more statistical invariants as a direct result of momentum conservation
applied to a large control volume embedded within the turbulence. This is
true for conventional hydrodynamic turbulence (isotropic or anisotropic),
as well as many geophysical systems such as MHD, rotating and stratified
turbulence. In some cases the invariant arises from conservation of linear
momentum, and in other cases from conservation of angular momentum. Usually
these invariants enforce an algebraic relationship between the integral
length and velocity scales, and so constrain the manner in which the
turbulence decays. Indeed, in many cases it is possible to derive explicit
decays laws for the kinetic energy, and these laws have been verified by
large-scale DNS for conventional and MHD turbulence. However, the
predictions for stratified and rotating turbulence remain untested.