Contributions of plasma simulations to physical understanding of surface dielectric barrier discharge for flow control (invited paper)

Abstract

Surface dielectric barrier discharge (DBD) has been widely studied as active flow control actuator. DBD plasma actuators have two flow control mechanisms: the electrohydrodynamic (EHD) force and gas heating. Plasma fluid simulations are powerful tool to analyse the plasma physics involved in surface DBD. In this review, an overview is presented focusing on plasma fluid simulations of DBD plasma actuators. For numerical modelling, the three species drift-diffusion model with Local Field Approximation is most generally adopted. The important physical insight obtained from the analysis is that the negative discharge plays a dominant role in the EHD force generation. The electric field shielding by electron accumulation on the surface prevents the streamer formation and this leads to the development of negative ion cloud and strong EHD force generation. For the gas heating, the short-time energy transfer from plasma to the air leads to the formation of micro-shock waves and to the flow modification. Furthermore, structural variations such as the multi-electrode configuration combining AC and DC voltage inputs have significant influence on the discharge. The DC voltage input enhances the ion drift motion and the electric field at the discharge front, which results in the elongation of streamer and EHD force enhancement.