Numerical Investigation of Backward Facing Step Flow over Various Step Angles

In this study, based on an open source CFD package OpenFOAM we carried out a number of numerical simulations using Reynolds Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) approaches. The numerical investigation has been implemented for various step angles (10o, 15 o, 20 o, 25 o, 30 o, 45 o, and 90 o), different expansion ratios (1.48, 2.00 and 3.27), and Reynolds numbers (5000, 8000, 11000, 15000, 47000 and 64000). The comparisons of the flow structures, separation flows and reattachment lengths between the numerical results and the observations show very good agreement. The results obtained from LES show a better agreement with the observations than the results obtained from RANS model.