Direct numerical simulation methodology is employed to analyze a two-dimensional separated and reattached flow and heat transfer around an inclined downward step in a plane channel. Treated in the present study is an expansion ratio of 1.5. The inclination angle of step α is systematically varied from 15° to 90°, and the Reynolds number Re from 100 to 1200. The flow is found to be steady at Re≤400 but become sensibly unsteady at Re=500. Heat transfer is promoted by the unsteadiness of flow and the Nusselt number increases in the neighborhood of the time averaged reattachment point.
