Drag reduction on a three-dimensional model vehicle using a wire-to-plate DBD plasma actuator

In this paper, we apply a wire-to-plate DBD plasma actuator to a three-dimensional model vehicle (called Ahmed body) for drag reduction at the free-stream velocities of U infinity=10-20m/s. An actuator with a thin wire of 11 mu m diameter as an exposed electrode is located at the front edge of the slanted surface of the Ahmed body, and its spanwise length and applied voltage are varied. The induced mean velocity by the actuator reaches up to about 4.2 m/s at the applied voltage of 9 kV. With actuation, the drag is reduced by the amount of maximum 10% at U infinity=10m/s. The maximum efficiency of the present actuator is 0.1-0.12 depending on the spanwise length of the actuator, applied voltage, and free-stream velocity. The present drag reduction and efficiency are higher than those of a conventional plate-to-plate DBD plasma actuator. With surface-pressure and PIV measurements, it is shown that the flow above the slanted surface is significantly affected by the spanwise length of the actuator, and the streamwise momentum induced by the actuator suppresses the flow separation at the front edge of the slanted surface and recovers the pressure on the slanted and vertical base surfaces, resulting in drag reduction. Graphic abstract