Large Eddy Simulations of the Richtmyer–Meshkov Instability in a Converging Geometry

This work presents on-going research on large-eddy simulations of shock-generated mixing in Richtmyer-Meshkov flow in converging geometries. A hybrid numerical method is used on each subgrid of the mesh hierarchy within the AMROC (adaptive mesh refinement object oriented C++) framework: it is a shock capturing method but reverts to a centered scheme with low numerical viscosity in regions of smoother flow. The stretched-vortex subgrid-scale model allows for the capturing of the small-scale mixing process between the two fluids. Results presented focus on the evolution of the mixing layer and its internal statistics including various spectra and p.d.f.s of mixed molar and mass fractions. A detailed quantitative analysis has also been conducted including space-time histories of instantaneous cylindrical shell-averages of diverse quantities, taken concentrically to the main shocks. Comparisons are made with the planar Richtmyer-Meshkov instability with reshock studied by Vetter and Sturtevant (1995) [1] and Hill et al. (2006).