For detailed study please go to Flow Reattachment: Flow over a Backward-facing Step documentation.
The flow of air over a backward-facing step is simulated, and the reattachment length is analysed. The geometry was meshed locally using blockMesh. The resulting mesh consists of 550000 volumes and is shown in the figure below.
The simulation validates the velocity profiles, coefficient of pressure and reattachment length. Post processing of results gives insight into the characteristics of reattachement. Shown below are contours of velocity over the step.