Oral presentation

A study of emerging turbulent scales entropy production is conducted for a supercritical shear layer as a precursor to the eventual modeling of Subgrid Scales (from a turbulent state) leading to Large Eddy Simulations. The entropy equation is first developed for.a real, nonideal fluid using a validated all-pressure fluid model, and the entropy flux and production terms are identified. Employing a Direct Numerical Simulation (DNS) created database of a temporal 3D supercritical shear layer using the fluid model, the different contributions to the irreversible entropy production term are evaluated. Both domain averaged and root-mean-square (RMS) terms are computed at three different stages of the DNS, representing the timewise ascending, culmination and descending branches of the spatially averaged positive spanwise vorticity. The unfiltered and filtered databases are compared to evaluate the relative importance of irreversible entropy production from viscous, Fourier heat diffusion and molar fluxes terms. The results show that the average entropy production is dominated by the viscous terms at all stages of the evolution; however, the contribution to the RMS of the molar flux term for both the ascending and descending branches is non-negligible. This latter result is traced to the molar gradients tending to be smeared by emerging turbulent scales