Exploring k and epsilon with Modified Spalart–Allmaras One–Equation Model

Abstract

Abstract: A wall–distance–free version of the Spalart–Allmaras (SA) one–equation model is proposed to account for the distinct effects of low-Reynolds number (LRN) and wall proximity. The turbulent kinetic energy k and the dissipation rate ε are evaluated using the ~vt–transport equation together with some empirical relations. The model coefficients/functions preserve the anisotropic characteristics of turbulence in the sense that they are sensitized to rotational and nonequilibrium flows. The model is validated against a few well-documented flow cases, yielding predictions in good agreement with the direct numerical simulation (DNS) and experimental data. Comparisons indicate that the present model offers some improvement over the Spalart–Allmaras one–equation model and competitiveness with the SST k–ω-model.

Main result: Contrasting the predicted results with measurements demonstrates that the new model returns predictions comparable with the SA/SST model in most of the flow cases considered herein. The proposed model is wall-distance-free and applicable to arbitrary topology in conjunction with structured/unstructured grids, which in turn render it advantageous to the SA/SST model.