COMPRESSIBILITY CORRECTION FOR THE SPALART-ALLMARAS MODEL IN FREE-SHEAR FLOWS

This paper presents a correction of the Spalart-Allmaras turbulence model to account for the compressibility effects in mixing layer flows. Unlike other corrections proposed for the K- epsilon model, the present correction does not need the knowledge of the turbulent Mach number and, therefore, can be applied to those turbulence models, like the Spalart-Allmaras one, which do not integrate directly the turbulent kinetic energy equation. To explore the validity of the proposed correction, four mixing layer flows and four supersonic backward facing step flows, covering a wide range of flow conditions, were selected and computed using both the standard and the corrected Spalart-Allmaras model. The analysis of the numerical results and their comparison with the experimental data show that the proposed correction produces a significant improvement of the numerical predictions.