Experimental characterization of a novel cyclotronic plasma actuator

A novel axisymmetric device with pulsed spark emission was developed as an active flow control alternative to passive vortex generators. The flowfield induced by the actuator was studied in quiescent flow. The current-voltage characteristics and power requirements of the high-voltage circuit that powered the discharge were detailed at different operating power levels. A descending current-voltage characteristic typical for electric breakdown was identified. Schlieren visualization was used to study the thermal effects of the plasma on the surrounding air. The induced flow velocity close to the actuator face was directly related to the influence of the rotating discharge, whereas the flow farther away from the actuator face was dominated by thermal instabilities. Phase-locked stereoscopic particle image velocimetry data were acquired across seven evenly-spaced planes perpendicular to the surface of the actuator at three different power levels. These data were used to reconstruct three-component volumetric averaged velocity fields. The induced velocity by the plasma discharge was found to increase with supplied power. Two-dimensional planes and three-dimensional isosurfaces were used to describe the induced flow and characterize the vorticity created during actuation. An annular vorticity region was discovered centered above the electrode gap.