Numerical study of mixing enhancement in a supersonic round jet

Experiments and computations are used to investigate the mixing enhancement of an underexpanded sonic jet subjected to radial secondary injections in a realistic aircraft-afterbody configuration. In accordance with more academic studies, the present study confirms that secondary jets lead to a strong distortion of the jet interface under the action of the longitudinal vortices. Reynolds-averaged Navier-Stokes computations are validated on experimental data and then used to perform a parametric study. We investigate the influence of parameters such as the number of active injectors, their aspect ratio, and the total pressure and temperature of the injected air. These computations also allow us to investigate the drastic changes in the compressible structure of the flow due to the action of the secondary injection.