A-priori direct numerical simulation assessment of sub-grid scale stress tensor closures for turbulent premixed combustion

The fidelity of large eddy simulations (LES) depends heavily on the closures of the sub-grid scale (SGS) stress tensor but most existing models have been proposed for non-reacting isothermal flows. However, the flame normal acceleration due to chemical heat release significantly affects turbulent flow statistics including the statistical behaviour of SGS stresses within flames but limited effort has been directed to the assessment of the SGS stress tensor closures in turbulent premixed combustion. In the present analysis, the closures of the SGS stress tensor have been a-priori assessed with respect to explicitly filtered direct numerical simulation (DNS) data of freely propagating turbulent premixed flames with a range of different values of turbulence intensities and the integral length scale to flame thickness ratios. A variety of scale similarity models has been considered in addition to the well-known static and dynamic Smagorinsky models. Further, a more recent development by Anderson and Domaradzki (2012) has been extended for compressible flows and included in this analysis. Detailed physical explanations have been provided for the observed model performances.