Theoretical investigation of supersonic flow control by nonthermal DC discharge

This work describes a theoretical study on shock wave modification by the electrical discharge generated with a DC voltage. Weakly ionized and high-density assumptions for nonthermal plasma were examined to demonstrate heat and momentum transfer contributions in supersonic flow control. The momentum equation for the plasma electrons and ions was considered to evaluate the changes in the incident flow velocity by the plasma. The change in the incident flow temperature was studied by applying source terms arising from a weakly ionized and high-density plasma to the energy equation. It was concluded that the momentum transfer from a nonthermal plasma into the incoming supersonic flow was responsible for the increasing shock wave angle. On the other hand, a nonthermal plasma with a remarkably high ionization degree increases the incident flow temperature drastically, while a weakly ionized plasma has a negligible effect on flow temperature. Our numerical results show that the electric field distribution has a significant role in the plasma flow control mechanisms, suggesting a new tailoring parameter via cathode geometry. The results of this work are in good agreement with respective experimental validation data and can be used in plasma-based shock wave control apparatus.