Compressibility effects in modelling turbulent high speed mixing layers

Abstract

For high speed shear layers, variable density extensions of standard incompressible turbulence models have not proved to be adequate in explaining the experimentally observed reduction in growth rate with increase in the convective Mach number. Recently, Sarkar et al. suggested that, in addition to modelling the pressure dilatation, another dilatational correlation ‐ the compressible dissipation ‐ should be considered because of the enhanced dissipation known to be present in compressible turbulence. They have used the compressibility‐corrected model ‐ limited to the second power of the turbulent Mach number ‐ with the SPARK code for the computation of high speed shear layers and have obtained satisfactory agreement with some of the available experimental data. This simple algebraic compressibility model has been modified to include a fourth order turbulent Mach number term. Comparison of the predictions with results of several analytical models and experimental work shows good agreement.