The similarity of shock waves generated by a cone-shaped plasma and by a solid cone in a supersonic airflow

A truncated 60° cone with a slender central spike, which protrudes to the tip location of a perfect cone, is designed as a wind tunnel model. It generates a bow shock in a supersonic airflow. This model is featured with an on-board discharge arrangement with the central spike and the truncated cone as two electrodes. When the central electrode is designated as the cathode, a dc pulsed discharge produces a hollow cone-shaped plasma that envelops the spike. The results show that this plasma has changed the original bow shock to a conical shock, equivalent to reinstating the model into a perfect cone and to generate a 70% increase in the body aspect ratio. A significant drag reduction in each discharge is inferred from the pressure measurements; at the discharge maximum, the pressure on the frontal surface of the body decreases by more than 30%, the pressure on the cone surface increases by about 5%, while the pressure on the cylinder surface remains unchanged. The energy loss due to wave drag is reduced to make up for the two-thirds of the energy consumed in the electric discharge for plasma generation. The measurements also show that the plasma effect on shock structure lasts much longer than the discharge period.