01. Experimental/Computational Fluid Dynamics

Plasma actuators (PAs) have attracted attention as active flow control devices for various engineering applications. A PA generally consists of two electrodes separated by a dielectric. An induced jet called an ionic wind is generated when high alternating current (AC) voltage is applied between the electrodes. In response to the recent social demand for the effective use of energy resources, it is expected that the ionic wind can be used to reduce drag of objects. To apply PAs to control the flow around objects, it is necessary to understand in detail the generation mechanism of ionic wind and their fluid control effect for driving PAs at appropriate positions and timings. However, various PAs have been proposed with different electrode shapes and positions, resulting in wide variations in ionic wind depending on the specific PA configuration. Therefore, there is a need for the clarification of the mechanism of ionic wind generation. Recently, the annular-type PA with circular electrodes have gained researchers’ interests, due to its unique feature: the direction of ionic wind flow is inverted depending on the radius of the circular electrodes. Elucidating the physical mechanism of the ionic wind reversal is necessary to improve the fluid control performance of PAs, most of which typically induce ionic wind in only one direction. The objective of this study is to elucidate the mechanism of ionic wind inversion induced by annular-type PAs. Previous studies have indicated that ionic winds are the result of two fluid-driven effects: electrohydrodynamic forces and gas heating. In this study, we employ numerical methods to investigate the induced flow reversal phenomenon. Our approach involves the use of plasma simulation and computational fluid dynamics (CFD), which allows us to consider both the electrohydrodynamic and gas heating fields. (288/300)