Flow visualization in cavity with dielectric barrier discharge actuator control

Abstract

The results of hydrodynamic pressure fluctuations control by means of a dielectric barrier discharge plasma actuator in a rectangular cavity with sharp edges are presented. The study was carried out at the free flow velocity V=37 m/s. The discharge was organized near the leading edge of the cavity. The average energy of the discharge pulse was 0.03 J, its duration was 1 ms, and frequency modulation was implemented at the natural cavity resonant frequencies of 500, 817, 1317 Hz and at a high frequency of 2160 Hz which did not correspond to the natural resonant pressure peak. Pressure pulsations were measured with a Kulite pressure transducer. It is established that the discharge regime affects the pressure fluctuations in the cavity. The pressure amplitude at the downstream wall of the cavity can be either increased from 117 dB to 128 dB or decreased to 110 dB if, respectively, if either the dominant or higher modes are pumped by the discharge. The PIV visualization was organized in the phase-locked mode. The pressure spectrum corresponds to the magnitude of coherent structures in the shear layer of the cavity. Keywords: plasma actuator, cavity, active control, DBD, boundary layer, mixing layer, closed loop.