Modeling of the subgrid scale viscous/scalar dissipation in compressible turbulence

Results are presented of subgrid scale (SGS) viscous/scalar dissipation models using {\it a priori} analysis of compressible turbulent flows. This is done via assessment of DNS of several turbulent flow configurations at varying compressibility levels, Reynolds and Schmidt numbers. These models will be used as sub-closures in the LES via FDF of compressible turbulence. Optimum model parameters are calculated by maximizing the correlation coefficients between the SGS exact and modeled terms, and optimal estimators are used to verify the results. The effects of the filter width are also assessed for sub-closures. Different methods for calculating the model coefficients are evaluated and it is shown that a dynamic procedure based on the global SGS equilibrium between the production and dissipation produces the best results.