Assessment of the Eddy Viscosity-Based Turbulence Models on the Solution of the Highly Separated/Attached Flow

Abstract

The present study investigated performance of different turbulence models based on the Reynolds-averaged Navier-Stokes (RANS) equations to solve the flow over a backward-facing step (BFS). Three different turbulence models, i.e., Spalart-Allmaras, Realizable k-↋ and SST k-ω turbulence models, were investigated for the flow over BFS. The investigations were performed for the Reynolds number of Reh = 9.6 x 103 based on step height, h, and the free stream velocity, U∞. The results, which are validated against the experimental data, showed that the Spalart–Allmaras model predicted the reattachment length, Xr, with an error of 9.52%. The Realizable k-↋ and SST k-ω models overpredicted the reattachment length, Xr, by 26.7% and 38.1%, respectively. Within the recirculation region, however, the SST k-ω provided the best prediction of the streamwise velocity, with a maximum difference of 5% from the experimental measurements. The largest local difference of 191% was obtained with the Spalart–Allmaras model at x/h = 1.