Parametric study on the mixing enhancement of parallel supersonic-subsonic wakes using wall cavities

A series of computational studies on the enhancement of parallel supersonic-subsonic mixing wakes, where M-1 = 1.78 and M-2 = 0.30 at baseline, is conducted and compared with available experimental data. The mixing problem of this parallel flow is characterized by the interaction of "complex'' turbulent shear flow with acoustic waves emitted from a wall-mounted cavity. The first aim of the present work is to show a direct comparison between numerical predictions and equivalent experimental data for the baseline case. Hence we make a comparison of eight independent turbulence models, which were selected from the most widely using turbulence models in use in the engineering field, consisting of six eddy -viscosity models and two Reynolds stress models. The Pitot pressure distribution data are in good agreement between computation and experiment, and the results show that Menter's SST model gives the best performance. Further, we investigate the effects of primary parameters such as the length-to-depth (L/D) ratio of the cavity, the position of the cavity, and the arrangement of the cavity at the given flow condition. Consequently, this methodology can contribute to finding an optimal guideline for the idea of mixing enhancement in the free turbulent wake using the acoustic wave produced by wall cavities.