Characterization of DC-Augmented Dielectric Barrier Discharge Plasma Actuators

Dielectric barrier discharge (DBD) plasma actuators for aerodynamic lift, drag, and separation control have gained popularity over the past decades. While offering several attractive features, such as instantaneous response and no moving parts, applications of DBD actuators are limited due to the relatively low forcing. A DBD actuator thrust can be augmented by applying DC potential downstream on the plasma discharge region. Parameterization of the DC-augmented (DCA) DBD can lead to understanding the actuator regimes and performance optimization. Characterization of 3-electrode DCA-DBD over the range of negative and positive DC on the third electrode and the effect of electrode spacing shows several distinct trends in the actuator behavior. Velocity and thrust measurements are presented for a range of voltages, frequencies, and geometric conditions. High-voltage downstream DC electrodes are found to increase the plasma actuator thrust by factor two compared to a traditional straight DBD actuator in positive DC; the onset of the counter-flowing jet is characteristic of a negative DC electrode. Time-resolved velocity profiles, discharge imaging, and discharge current analysis shed insights into the underlying actuator behavior and its interaction with the fluid.