Schlieren Imaging of Flow Actuation Produced by Direct-Current Surface Glow Discharge in Supersonic Flows

Schlieren imaging of flow field structure produced by direct-current surface glow discharges in diffuse mode is studied experimentally in the presence of Mach 2.85 supersonic flow. An array of four discharge pairs with a total discharge power of about 150 W is established just upstream of a 30deg wedge. Schlieren imaging reveals that for cathodes located upstream of the anodes, the discharge produces significant interaction with the flow, by changing the attached oblique shock structure at the foot of the wedge, while this interaction effect is completely absent in the cathode downstream case. We conclude that gas-heating-related dilatational effect alone cannot explain the observed phenomena.