Influence of the discharge location on the performance of a three-electrode plasma synthetic jet actuator

Plasma synthetic jet actuator (PSJA) is a novel device for high speed flow control. This paper reports both the schlieren measurement and the CFD simulation results of the discharge location's influence on the performance of a three-electrode PSJA. The schlieren images qualitatively show that discharge location has a significant influence on the PSJA performance. The CFD simulation results quantitatively indicate how the discharge location affects the energy distribution and evolution. When the discharge is near the orifice, the gas near the orifice is heated firstly, and the expelled gas takes away more energy at the initial jet stage. On the contrary, when the discharge is far from the orifice, the expelled gas temperature is lower at the initial jet stage, and the expelled gas takes the energy away much slower. The results demonstrate that, as discharge location closer from the orifice, the jet velocity at the actuator exit increases faster and also decreases faster, showing a strong pulsing characteristic. With farther discharge location from the orifice, the jet exit velocity increases slower, but can keep a relative high value for a longer time, which means a longer duty cycle. Farther discharge location from the orifice also leads to the increase of both the jet momentum and the expelled mass per pulse.