PIV Study on Flow Characteristics of Periodic-Pulsed Dielectric-Barrier-Discharge over A Conical Forebody

摘要

The momentum-transfer performance of a plasma actuator over a 20° conical fore-body is studied experimentally for the effects of periodic pulse in the absence of external flow. A two-dimensional particle image velocimetry is used to measure cross flow velocity field around the body in atmospheric air. The time-averaged spatial and temporal distributions of induced maximum cross flow velocity and maximum magnitude of axial-vorticity in the neighborhood of the body are investigated. Under pulsed actuation the unsteadiness of the induced flow is significant in the flow physics, therefore, besides the ensemble-averages, phase-locked-averages are examined. Experimental results indicate that the main mechanism of momentum transfer under periodic pulsed actuation is the formation of strong discrete vortices, rather than the gas acceleration. The phase-locked averaged maximum cross flow velocity and maximum magnitude of axial vorticity induced by periodic-pulsed discharge remain non-zero even after the actuator is turned off. The results reveal the effect of flow hysteresis. The input power can be saved by using periodic pulsed actuation that is able to utilize the flow hysteresis.