A highly-resolved numerical study of turbulent separated flow past a backward-facing step

A numerical study of fully-developed turbulent flow past a backward-facing step is performed to analyze the effect of mesh refinement on the computed results. The time averaged equations of conservation of mass and momentum are solved by a finite-volume method using two versions of the K-ε model of turbulence. The computations are performed with both the standard and the non-linear K-ε turbulence models for 166 × 73 and 332 × 146 mesh points. The comparison of the results with available experimental findings indicate that nonlinear terms must be incorporated into the K-ε model to account for normal stress differences, and that even with very fine resolution, the standard K-ε model fails to provide accurate predictions of the flow field.