Semiempirical Thrust Model of Dielectric Barrier Plasma Actuator for Flow Control

Abstract

Asymmetric dielectric barrier discharge plasma generating a wall-bounded jet without mechanical moving parts was studied as a flow control device. A reliable model providing thrust value of the plasma actuator is difficult to develop without incurring a heavy calculation cost attributable to its unsteady characteristic and asymmetric electric field distribution. In this paper, a new semiempirical thrust prediction model was developed based on the one-dimensional electrohydrodynamic effect. It is implemented in a computational fluid dynamics solver as a body force term. We determined that the thrust of the plasma actuator is proportional to the energy consumed in the actuator, which is regarded as a capacitor in the alternating current (AC) circuit. An analytic estimation of the capacitance of the actuator is performed, and the sensitive design parameters dielectric constant, thickness and the upper electrode thickness are considered in the capacitance value. The thrust value from the model is inserted as a body force term in a Navier-Stokes equation solver and the body-force region is specified by the extent of the region of the discharged plasma. Grid dependence of the model is verified and the velocity profile changed by the actuator is compared with previous reference experiment data to validate it. Thus, the authors conclude that the developed model can provide the proper thrust value and a two-dimensional velocity profile without incurring a heavy calculation cost.