Stephan Fauve obtained a PhD in 1984 at ENS-Paris and became Professor in 1987 to set up the activities in experimental physics in the newly created ENS-Lyon (acoustics in liquid-vapor mixtures, ultrasound scattering by vorticity in turbulent flows, instabilities of granular flows, observation of quasi-crystalline order in pattern-forming instabilities, fluctuations of injected power in turbulent flows. He has initiated a dynamo experiment using a von Karman swirling flow. In 1997, he moved back in 1997 to work on Statistical properties of fluctuations in dissipative systems driven out of equilibrium, acoustics in foams, observation of the dynamo effect in a turbulent flow of liquid sodium (in collaboration with part of his former group in Lyon and CEA); observation of reversals of the magnetic field; studies of wave turbulence and of the statistical properties of large scales in turbulence. He obtained many prestigious Awards during his career including the CNRS Silver Medal in 2009, Professor at Institut Universitaire de France Junior in 1992-1997 and senior in 2009, the CEA Académie des Sciences Award in 2009 and he is member of the French Acadamy of Science since 2011.
Dynamics of large scales in turbulent flows
Abstract: In many turbulent flows, scales larger than the forcing scale display equipartition of energy. This familiar result of equilibrium statistical physics could look surprising in turbulent flows which are considered as a canonical example of an out of equilibrium dissipative system. After displaying several examples and discussing this result, we show that concepts from equilibrium statistical physics can also be used to describe transitions between different turbulent regimes when a governing parameter is varied. More precisely, the truncated Euler equation provides a tool to describe the dynamics of large scales and bifurcations that occur on a turbulent background. Finally, we show how the dynamics of these large scale is related to 1/f type noise observed in many turbulent flows and elsewhere.
27 May 2021, 16h3017h30
Webinar (please contact F. Romano for the link)
