Plasma-Gas Flow Interaction of a Discharge Normal to a Bluff Body Wake

This paper describes the interaction of a gas discharge with an air flow consisting of the wake of a flat plate normal to the airstream. The plate acts both as a bluff body and discharge electrode; the free discharge in the absence of the airstream and free airstream without discharge are orthogonal to each other. The electric forces involved in the free discharge and inertial forces involved in the free airstream are of the same order. The experiment has been carried out in a suitable duct, and the facilities include devices for discharge current measurements, hot wire anemometer, and visualization system. The analysis of the time histories obtained from the hot wire signals and cathodic current signals reveals the existence of an airstream-discharge coupling phenomenon, appearing as synchronized oscillations of the flow and discharge current.