Combination of counterflow jet and cavity for heat flux and drag reduction

Abstract

In the present work, a computational study is carried out to explore the potential of a combination of a forward-facing cavity and a counterflow jet for drag and heat flux mitigation for an axisymmetric body in a supersonic free stream of Mach 2. A comparison between the axisymmetric body with a forward-facing cavity and counterflow jet and the baseline geometry without the cavity and jet is made. The first part of this study focuses on capturing the transition point of the two counterflow jet modes, Long Penetration Mode (LPM) and Short Penetration Mode (SPM), by changing the pressure ratio of the nozzle. It gave an appropriate nozzle operating pressure selection based on the design requirement. The LPM is found to be suitable when only drag reduction is required, while the SPM provides both drag and heat flux reduction, but at a higher operating jet pressure. Next, a study is conducted to characterize the effect of the angle of attack on system performance. The LPM shows improvement over the baseline geometry for only a narrow range of angles of attack, while the SPM provides improved performance for a wider range of angles of attack. The effect of cavity and cavity dimensions on performance is then studied.