Wall-distance-free modifications to Spalart-Allmaras turbulence model

摘要

A wall-distance-free modification to the Spalart-Allmaras (SA) one-equation turbulence model is proposed and evaluated. The k and ∈ that render the hybrid time scale, are determined using the υ-transport equation together with the Bradshaw and other empirical relations. The model coefficients and other emperical functions are constructed so as to preserve the anisotropic characteristics of turbulence for application to non-equilibrium turbulent flows. The modified SA model is applied to calculate a few well-documented flows, yielding predictions in good agreement with the direct numerical simulation (DNS) and experimental data. Comparisons demonstrate that the modified SA model offers some improvement over the original SA model and competitiveness with the SST k-ω model.