Abstract: This study focuses on the flow and heat transfer characteristics of high-speed airflow over the rough-wall which has periodic roughness and small amplitude. By using the OpenFOAM program, flows on the semi-infinite sinusoidal wavy plates under different inflow conditions are numerically studied. The results show that there is a direct correlation between the wall heat flux coefficient C_Q and the total drag coefficient C_D. For the attached flow, C_Q/C_D only depends on the equivalent roughness h, which is the ratio of the roughness to the thickness of the boundary layer. When the flow separation occurs, C_Q/C_D no longer changes with roughness and only depends on the position variable x, which is defined by the similar transformation.

Key words: wavy rough wall, high-speed flow, ratio of heat flux coefficient to drag coefficient