An experimental study is performed for channel flow over a backward-facing step with the dielectric barrier discharge plasma actuator (DBD-PA). The plasma actuator consists of two metallic electrodes mounted on both sides of a dielectric plate. The actuator is installed on the corner edge of the step. The Reynolds number based on the mean velocity at the inlet and the step height ranges from 860 to 3240. The wall static pressure is measured, and the pressure loss coefficient is evaluated. The velocity profiles and turbulent intensities are measured by a PIV system at the Reynolds number of 1080, 1520 and 2170. The results show that the pressure drop at the step decreases by the effect of induced flow with the plasma actuator and the reattachment length is shorter compared with that of the steady flow condition. When the wave form with voltage of 6 kV and frequency of 2 kHz is applied to the electrode, the maximum pressure loss reduction rate of 31% is confirmed in the laminar flow region.
