The flow dynamics and mixing process of a sonic ethylene jet into supersonic air crossflow is numerically investigated based on the large-eddy-simulation (LES) technique, with special attention given to the near-injector and near-wall turbulence treatment. The salient turbulent, vortical, and shock structures are examined to identify the mechanisms dictating the supersonic mixing layer. Results reveal that the periodic shedding of shear-layer vortices accounts significantly for the crossflow entrainment through the stretching-tilting-tearing mechanism. The calculated mixing is qualitatively comparable to the experimental data. The possible roles of the low-speed regions, both ahead of the jet and in the wake region, are also explored to further elucidate the system characteristics.
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