Wall Normal Jet Produced by DBD Plasma Actuator With Doughnut-Shaped Electrode

Properties of coaxial annular jets produced by a dielectric barrier discharge (DBD) plasma actuator with a doughnut shaped electrodes were investigated under atmospheric pressure and room temperature. The actuator consists of two circular electrodes sandwiching a thin dielectric layer. By applying 0 – ±3.3 kV between the electrodes at radio frequencies, the plasma jet is formed near the inner edge of the top electrode. The radial jet runs toward the center of the electrode and then impinges at the center to generate a wall normal annular jet. The evolution of the wall normal jet was observed precisely using particle image velocimetry (PIV) system. It was found that characteristic velocities increase in proportion to the bursting frequency and inversely proportional to the inner diameter of the electrode at the surging time of the voltage at 5.0 × 10⁻⁶sec.