INVESTIGATION OF INLET EFFECTS ON BACKWARD-FACING STEP FLOW PREDICTION

Abstract

The turbulent flow over backward-facing step (BFS) is numerically investigated by using FLUENT (R) code. Both uniform and non-uniform velocity profiles are used as inlet boundary condition. Five different Reynolds averaged Navier-Stokes (RANS) turbulence models are employed. The Std. k-omega model shows the best agreement with the experimental data among the models used under the conditions considered in this study. The results show that using a uniform velocity profile has a negative effect on predictions if the domain is not sufficiently extended upstream from the inlet. To eliminate this effect, the domain should be extended upstream by about 10D(h) from the inlet. However, results show that this extension causes absorption effects of inlet parameters such as inlet turbulence intensity.