Mechanisms and Responses of a Single Dielectric Barrier Plasma Actuator: Geometric Effects

摘要

The single dielectric barrier discharge plasma, a plasma sustainable at atmospheric pressure, has shown considerable promise as a flow control device operating at modest (tens of watts) power levels. Measurements are presented of the development of the plasma during the course of the discharge cycle, and the relevance of these measurements to the modeling of the actuator's electrical properties is discussed. Experimental evidence is presented strongly pointing to the electric field enhancement near the leading edge of the actuator as a dominant factor determining the effectiveness of momentum coupling into the surrounding air. It is shown that the thrust produced by the actuator depends directly on the thickness of the exposed electrode even when the bulk discharge properties of the plasma remain unchanged. The case for field enhancement is bolstered by the application of an analytical model in closed form that, although an abstraction of the real actuator geometry, indicates that electric forces on charge imbalance in the plasma are concentrated predominantly near the edge of the exposed electrode. Both of these results are consistent with computational fluid dynamics calculations of the actuator in operation.