Experimental Investigation of Pulsed Dielectric Barrier Discharge Actuators in Sub- and Transonic Flow

Experiments were conducted in order to investigate the ability of nanosecond pulsed dielectric barrier discharge (ns-DBD) actuators to control flow on airfoils in subsonic and transonic flow (up to Ma1 = 0.75, Re = 1.35 • 10^6). A NACA 0015 profile equipped with a leading edge mounted ns-DBD actuator was investigated up to Re = 2.3 • 10^5 (u1 = 24 m/s). Measurements of the surface pressure distribution clearly confirm the actuator’s potential to delay leading edge separation. In the following the impact on the control authority of different voltage pulse parameters, such as voltage amplitude, actuation frequency and rise/fall time of the pulse were investigated. The experiments in transonic flow were conducted on a NACA 3506 compressor blade profile. A ns-DBD actuator was placed at x/c = 0.33 where the foot of the shock-wave and boundary-layer separation was observed. Schlieren flow visualization showed the shock-wave boundary-layer interaction and was used to investigate the actuator’s effect on the shock position and shape. A high-speed camera allowed to acquire schlieren images at high acquisition rates and investigate as well the movement of the shock in the frequency domain. These results were verified with measurements of the static pressure at the side wall using unsteady pressure transducers.