MODELING OF SUPERSONIC TURBULENT COMBUSTION USING ASSUMED PROBABILITY DENSITY-FUNCTIONS

Recent calculations of turbulent supersonic reacting shear flows using an assumed multivariate beta probability density function (PDF) resulted in reduced production rates and a delay in the onset of combustion. This result is not consistent with available measurements. Earlier work was based on a one-equation turbulence model that required a specification of the Length scale, PDFs that did not yield Favre-averaged quantities, and the gradient diffusion assumption. The present work incorporates a two-equation turbulence model based on a kappa-omega formulation, a PDF that yields Favre averages, and relaxes the gradient diffusion assumption. Results suggest that the form of the assumed multivariate PDF and the gradient diffusion assumption are the main causes of the discrepancy.