Tuesday, February 4, 2020
5:15 p.m. — room conf IV (24 rue Lhomond)
The organization of fluid systems into a turbulent layer adjacent to a stably stratified one is common both in Nature (atmospheres, stellar interiors, ...) and in the industry (e.g. nuclear power plant in accidental configurations). Understanding the exchanges of mass and momentum at the interface and the coupled dynamics of such systems is challenging, because of the large range of involved time- and length-scales, from the rapid small-scale turbulence associated to the excitation of propagating waves, to their longterm non-linear interactions associated to large-scale circulations. I will present the results of various experimental investigations of idealised configurations, complemented by numerical simulations : a turbulent jet impinging a density interface, the convection in water around 4 degree Celsius, etc. Applications in meteorology, stellar evolution, and nuclear safety, will be addressed.