Wall-Distance-Free Version of Spalart–Allmaras Turbulence Model

A wall-distance-free modification to the Spalart–Allmaras one-equation turbulence model is proposed and evaluated. The and that render the hybrid timescale are determined using the transport equation together with the Bradshaw and other empirical relations. The model coefficients and other empirical functions are constructed to preserve some anisotropic characteristics of turbulence for application to nonequilibrium turbulent flows. The modified Spalart–Allmaras model is applied to calculate a few well-documented flows, yielding predictions in good agreement with the direct numerical simulation and experimental data. Comparisons demonstrate that the modified SA model offers some improvement over the original Spalart–Allmaras model and is competitive with the shear-stress transport model.