Shock Wave Control by Nonequilibrium Plasmas in Cold Supersonic Gas Flows

• Published in: AIAA journal 2001-08, Vol.39 (8), p.1547-1552
• Main Authors: Merriman, Samuel, Ploenjes, Elke, Palm, Peter, Adamovich, Igor V
• Format: Article
• Language: English
• Subjects: Boundary layers; Electric discharges; Exact sciences and technology; Flow visualization; Gases; High pressure effects; Ionization of gases; Ionization of plasmas; Magnetohydrodynamics; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Plasma flow; Plasma properties; Shock waves; Shock waves and discontinuities; Supersonic flow; Thermal effects; Waves, oscillations, and instabilities in plasmas and intense beams
• ISSN: 0001-1452; 1533-385X
• DOI: 10.2514/2.1479

Experimental studies of shock modification in weakly ionized supersonic gas flows are discussed. In these experiments, a supersonic nonequilibrium plasma wind tunnel, which produces a highly nonequilibrium plasma flow with the low gas kinetic temperature at M = 2, is used. Supersonic flow is maintained at complete steady state. The flow is ionized by a high-pressure aerodynamically stabilized dc discharge in the tunnel plenum and by a transverse RF discharge in the supersonic test section. The dc discharge is primarily used for the supersonic flow visualization, whereas the RF discharge provides high electron density in the supersonic test section. High-pressure flow visualization produced by the plasma makes all features of the supersonic flow, including shocks, boundary layers, expansion waves, and wakes, clearly visible. Attached oblique shock structure on the nose of a 35-deg wedge with and without RF ionization in an M = 2 flow is studied in various nitrogen-helium mixtures. It is found that the use of the RF discharge increases the shock angle by 14 deg, from 99 to 113 deg, which corresponds to a Mach number reduction from M = 2.0 to 1.8. (Author).