Application of a Variable-Density Turbulent Mixing Model to a High-Resolution Richtmyer-Meshkov/Reshock Simulation*

Recently, it was shown that constructing a model for turbulent mixing of a fluid interface leads to a telegraph equation indicating diffusion- and wave-like behaviors of the expanding interface (Doss, Physics Letters A, 430, 2022). Applied to Richtmyer-Meshkov instability in which turbulence decays after a shock passes the interface, this model predicts the dependence of fine-scale mix on initial parameters such as the perturbation spectrum. The model also elucidates the relationship between instability growth rate and fluid mixedness. High-resolution simulations of a shock wave passing a perturbed two-fluid interface (Wong, Baltzer, Livescu & Lele, Physical Review Fluids, 7, 2022) provide detailed statistical profiles and evolutions to compare the model's predictions. These simulations include both an initial shock and reshocking of the interface; conclusions in relation to the model are presented in both regimes.