The interaction between a sonic transverse jet and an oblique shock wave in a supersonic crossflow

Abstract

The development of air-breathing propulsion systems as a mean to propel high-altitude high-speed transport and single-stage-to-orbit (SSTO) vehicles promises to be a viable alternative to chemical rocket propulsion. In order to enhance mixing, an oblique shock wave is introduced into the combustion chamber as a source of baroclinic vorticity as well as a static temperature and pressure augmenter. An experimental campaign was conducted in the ST-15 supersonic test facility at Mach 2 to analyse the effect of three main control variables: the jet momentum flux ratio, the flow deflection angle and the impingement position of the shock on the jet plume. Measurements were acquired with Schlieren photography and stereo PIV techniques. Results suggest that, while near-field momentum-driven mixing remains unaltered following the introduction of the impinging shock wave, mid-to-far-field mixing mechanisms do change. An increase in the jet plume elevation was observed together with one in lateral expansion as a consequence of the introduction of a shock wave. Also, the formation of a strong shear layer downstream of the jet was observed, which acts as a source of vorticity to promote entrainment towards the jet mid-field. A stronger wave was noticed to produce more optimistic results for the mixing performance. This effect was seen to decrease with the introduction of a weaker shock or by shifting the strong shock downstream.