Formulation of a two-scale transport scheme for the turbulent mix induced by Rayleigh-Taylor and Richtmyer-Meshkov instabilities.

We develop a two-scale transport model for the turbulent mix induced by Rayleigh-Taylor and Richtmyer-Meshkov instabilities. We generalize the buoyancy-drag model by adding an energy equation for a more complete description of the generated interpenetration between heavy and light fluids. The generalized buoyancy-drag model, in turn, provides an appropriate source to the two-equation turbulence model, which is most suited for the induced turbulent flows. The two-scale transport model has been validated and several illustrative examples will be presented.