Résumé / Abstract Seminaire_GReCO
SÉMINAIRE DU GRECO

"A statistical mechanics approach to geophysical turbulence"

Corentin Herbert
Ecole Normale Supérieure de Lyon (ENS-Lyon) (Lyon, France)

The incentive for studying geophysical turbulence is twofold. First, it is a crucial ingredient of atmospheric and oceanic dynamics, which exhibit a rich and complex behavior, directly impacting our ability to forecast the weather and understand past and future climate changes. Second, it provides a fascinating playground for theoretical ideas stemming from statistical physics. Indeed, statistical theories may be built for this kind of turbulent fields, which have no equivalent in the classical framework of homogeneous isotropic turbulence. In this talk, I will show in particular that geophysical flows have non-trivial equilibrium states, and that their non-equilibrium behavior can be approached by perturbative methods due to the appearance of a time-scale separation regime. Under certain circumstances, this allows us to obtain explicit formulae for quantities such as the mean-flow and the Reynolds tensor, which is very rare in turbulence. Finally, I will discuss the abrupt transitions undergone by turbulent flows and how to study them with large deviation theory.

lundi 30 janvier 2017 - 11:00
Salle des séminaires Évry Schatzman,
Institut d'Astrophysique de Paris

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