Compressibility effects in Rayleigh-Taylor flows: influence of the stratification

The effects of a strong initial density stratification in a Rayleigh-Taylor instability for two miscible compressible fluids is studied by means of linear stability analysis and direct numerical simulations. As expected, stratification first annihilates turbulence production by smoothing the initial density jump. In the second step, a freely decaying regime, the turbulence homogenizes mixing inside the turbulent region, although the layer thickness does no longer grows significantly. Turbulence and mixing characteristics are detailed.