Abstract
Experiments have been performed for a turbulent channel flow over a backward-facing step. The backward-facing step flow is actively controlled by equipping the slit at step corner and low momentum fluids in the recirculating region are sucked from the slit. The width of the slit is changed 2,3 and 5mm, and suction flow rate is varied from 0.00 to 0.15. The wall static pressure and local heat transfer coefficient are measured behind the backward-facing step. In addition, the wall shear stress and velocity profile are measured by the micro flow sensor and split hot film probe. It is found that the heat transfer and pressure drop characteristics are controlled by suction flow rate, independently of suction velocities. When suction flow rate is 0.08,the highest performance is obtained.
