Simulation of Direct-Current Surface Plasma Discharges in Air for Supersonic Flow Control

Abstract

A computational model of a plasma discharge for supersonic air flow control is presented. Themodel is based on a self-consistent, multispecies, continuum description of the plasma with finite-rate chemistry effects. The plasma model is integrated with a compressible Navier–Stokes solver to study the coupled physical effects of the plasma interactingwith aM 3 supersonicflowat freestreampressure of 18 torr and the corresponding effects of theflowon the discharge structure in two dimensions. The species concentrations and gas temperature are examined in the absence andpresence of bulk supersonicflow.The peak gas temperature from the computations is found to be 1180K with the surface plasma alone in the absence offlowand830K in the presence of supersonicflow.Different ion species are found to be dominant in the absence and presence of supersonic flow, highlighting the importance of including finite-rate chemistry effects in discharge models for understanding plasma actuator physical phenomena. Electrode polarity effects are investigated, and the cathode upstream actuation is found to be stronger than the actuation strength with the cathode downstream, which is consistent with experimental findings of several groups.