Flow field around a spanwise-inclined jet in supersonic crossflow

Abstract

Implicit large eddy simulations were performed to reveal the flow field around a spanwise inclined jet in supersonic crossflow at Mach number M=2.5 and momentum thickness Reynolds number Reθ=7000. Flow features are similar to perpendicular injection, however, more complex and asymmetrical. This asymmetry results in the formation of an oblique bow shock and separation region upstream of the jet-injection and an oblique quasi-herringbone separation region in the near-wall jet wake. In addition to the major counter-rotating vortex pair, secondary counter-clockwise-rotating surface-trailing vortices are induced by the recirculating flow in the jet-leeward separation region and in the reattachment valley. These vortices merge into a single counter-clockwise-rotating surface-trailing vortex. Furthermore, the interaction within the major counter-rotating vortex pair induces a clockwise-rotating surface-trailing vortex. In the far-field downstream, the upper trailing vortex merges with the counter-clockwise-rotating major vortex, which contributes to the uneven shape of the major counter-rotating vortex pair. A 3D DMD analysis revealed the low-frequency dynamics of the shock structures, generation of vortices, and their interaction and momentum redistribution across the boundary layer. The latter effect, combined with the observation that the outer flow is only disturbed to a small extent and in the direct vicinity of the injection location, makes injecting spanwise-inclined jets into a turbulent crossflow a suitable technique for separation control applications.