Effect of counterflow argon plasma jet on aerodynamic drag of a blunt body at hypersonic Mach numbers

Abstract

An experimental investigation of aerodynamic drag reduction by counter How plasma jet injection from the stagnation region of a hemispherical blunt cylinder model flying at hypersonic Mach numbers are presented. Experiments are carried out in a hypersonic shock tunnel at four different jet-to-pitot pressure ratios namely 15·3, 24·52, 72·5 and 96·67 and three supply powers, namely 1·8KW, 2·7KW and 3·6KW. The flow fields around the test model are visualised using high speed schlieren technique. Direct force measurement is also performed using a single component accelerometer balance. The weakly ionised argon plasma jet has an electron temperature around 6,400K and electron number density ∼1.64 × 1015cm3. With plasma jet at pressure ratio 72·5 and 1·8K.W supply power the reduction in drag is found to be ∼28% (more than its cold jet counter part) although the plasma jet momentum is less than its cold jet counter part.