Experimental investigation on periodic characteristics of high-frequency oblique slot plasma synthetic jet actuator

Abstract

A plasma synthetic jet actuator with a high-frequency oblique slot was designed for supersonic flow control. The actuator's periodic operation characteristics were investigated using electrical parameter measurements and high-speed schlieren techniques. Experimental findings indicate that the actuator can stably operate within the frequency range of 0–2400 Hz. With increasing operating frequency, the breakdown voltage, maximum current, and discharge energy decrease, while the energy efficiency of the discharge increases. Moreover, the experiment revealed for the first time that an increase in the number of charged particles within the cavity leads to a decrease in breakdown voltage, and the concentration of charged particles reaches saturation at approximately 1200 Hz. High-speed schlieren observations indicate substantial inter-cycle influences in the periodic jet. At higher operating frequencies, the impact of inter-cycle flow field effects becomes more pronounced. The oblique slot plasma synthetic jet exhibits clear directionality in the distribution of shock waves and jet. The oblique slot jet also shows a significant wall attachment effect. These characteristics are beneficial for enhancing the flow control capability of the actuator. At 1200 Hz, the actuator achieves a discharge efficiency of 63% and a maximum jet front velocity of 309 m/s, showcasing its superior overall performance.