Abstract: The flow and heat transfer characteristics of surface with circular holes are studied by numerical simulation method. Four different conditions are simulated. The simulation results of heat transfer surface nusselt numbers are compared to the nusselt numbers which are calculated by Dittus-Boelter equation. The differences are less than 5%. The research results manifest that, in the four conditions, the model with circular holes surface has obvious effect on drag reduction. Because the circular holes change the flow structure of boundary layer near the surface which makes the normal velocity gradients perpendicular to the surface smaller and makes the boundary layer thickened. And because of part of momentum transfer from the outside of boundary layer is absorbed by the fluid under the circular hole surface, the turbulent disturbance near the wall and the wastage reduces. The calculation results show that the existence of surface with circular holes make the flow models have different effects of drag reduction and the best effect of drag reduction obtained in the simulations of four conditions is 14%,but as the drag reduction increasing, the heat exchange performance gradually weaken.

Key words: Drag reduction, Flow structure, Numerical simulation, Wall shear stress