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.
ASJC Scopus subject areas
- Condensed Matter Physics