Simulation of convective instabilities inside a supercritical fluid layer under Rayleigh-Benard configuration

The hydrodynamic stability of a near critical fluid initially at rest and a t thermodynamic equilibrium in a 2D square cavity heated from below (Raylei gh-Benard configuration) is studied. Due to the piston effect (specific to near critical fluids), the thermal field exhibits a very thin hot thermal b oundary layer at the bottom and a cooler boundary layer on the upper wall, which is kept at the initial temperature. We analysed the stability of the two boundary layers by solving the Navier-Stokes equations written for a Va n der Walls gas above its critical point. The results are compared with tho se issued from theoretical stability analyses.