Study of pressure redistribution under plasma filament effect on shock wave reflection

Abstract

This work focuses on the experimental study of near-surface filamentary plasma interactions with an impinging shock wave (SW) aiming for active control of duct-driven shock-dominated flows. Tests were performed at the supersonic blowdown wind tunnel SBR-50 of the University of Notre Dame at M=2 and varying stagnation conditions. Previous studies dealing with a multi-filamentary plasma pattern demonstrated pressure redistribution over the wall due to presence of longitudinal subsonic zones induced by each plasma filament. In current work, single or three plasma filaments were arranged on the test section surface to explore the effect of SWs interference. For detailed investigation of the pressure redistribution, the wall with the plasma filament(s) and impingent SW was equipped with multiple pressure ports. Additionally, acetone vapors were introduced to the working gas to allow mapping (visualization) of the SWs geometry using planar Mie scattering. This work shows that, for a single plasma filament interaction with the impinging SW, a new semi-conical SW is formed in front of the initial SW. In the case of three plasma filaments, the SWs interference leads to formation of a close-to-planar SW originating from the electrodes line. The intensity of this new SW closely matches the initial SW.