Aerodynamic drag reduction by plasma and hot-gas injection

The influence of plasma and hot-gas injection from a model's surface toward the external flow on aerodynamic drag of the model is researched. Experimental tests are conducted in transonic and supersonic wind tunnels at Mach numbers M-infinity = 0.59-4. Numerical experiments are carried out using unsteady Euler equations of an ideal perfect gas in integral conservative form. The calculations were performed at the oncoming Mach number M-infinity = 4, constant jet stagnation pressure, and jet stagnation temperatures of 600, 2000, and 6000 K. The investigations showed that the plasma or hot-gas injection can be used to reduce drag at subsonic, transonic, and supersonic Mach numbers, resulting in twice (or more) drag reduction. The calculations are in general agreement with the experimental data. The amount of drag reduction depends on jet stagnation temperature.