On the effects of the upstream conditions on the transition of an inclined jet into a supersonic cross-flow

The objective of this work is to explore and assess the effects of upstream conditions on the transition of an inclined jet into a supersonic cross-flow. The flow studied matches the experimental conditions of a sonic helium inclined-jet into a supersonic air cross-flow at Mach 3.6 by Maddalena, Campioli & Schetz (2006). We have performed large-eddy simulation with sub-grid scale (LES-SGS) stretched vortex model of turbulent and scalar transport developed by Pullin and co-workers. We have adopted a hybrid numerical approach with low numerical dissipation that uses tuned centered finite differences (TCD) in smooth flow regions, and weighted essentially non-oscillatory (WENO) scheme around discontinuities and ghost-fluid boundaries. The LES results show that the main flow features generated by the gas-dynamics interaction of the jet with the cross-flow, such as barrel shock, Mach disk, shear layer, and counter-rotating vortex pair, are numerically captured. Comparison of the LES results with the experiments are discussed. The transition and spatial development of the helium jet are strongly dependent on the inflow conditions of the cross-flow. Thus, turbulent inflow conditions are necessary for the prediction of dispersion and mixing of a gaseous jet in a supersonic, turbulent cross-flow.