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Accueil > Équipes > Équipe MEIGE > Diffusion scientifique > Séminaires internes

Internal wave–boundary layer coupling for a disc oscillating in a density-stratified fluid

Bruno Voisin, 22/03/2012

A horizontal circular disc oscillating in a density-stratified fluid radiates internal gravity waves. Viscosity affects both the propagation of the waves through the fluid and their generation at the disc. The second aspect, namely the coupling of the waves and the boundary layer at the disc, is seldom considered. For this, an assumption of large Stokes number is usually invoked. We compare the various linear theories of the problem — inviscid or viscous and with free-slip or no-slip boundaries — with one another and with two series of experiments : experiments from 2007 in Yuli Chashechkin’s group at the Institute for Problems in Mechanics in Moscow, and new experiments from 2011 at ENS de Lyon with Sylvain Joubaud and Thierry Dauxois.