COMPRESSIBILITY EFFECTS IN MODELING TURBULENT HIGH-SPEED MIXING LAYERS

For high speed shear layers, variable density extensions of standard i ncompressible turbulence models have not proved to be adequate in expl aining the experimentally observed reduction in growth rate with incre ase in the convective Mach number. Recently, Sarkar et al. suggested t hat, in addition to modelling the pressure dilatation, another dilatat ional correlation - the compressible dissipation - should be considere d because of the enhanced dissipation known to be present in compressi ble turbulence. They have used the compressibility-corrected model - l imited to the second power of the turbulent Mach number - with the SPA RK code for the computation of high speed shear layers and have obtain ed satisfactory agreement with some of the available experimental data . This simple algebraic compressibility model has been modified to inc lude a fourth order turbulent Mach number term. Comparison of the pred ictions with results of several analytical models and experimental wor k shows good agreement.