Numerical study of micro-ramp vortex generator for supersonic ramp flow control at Mach 2.5

An implicit large eddy simulation, implemented using a fifth-order, bandwidth-optimized weighted essentially non-oscillatory scheme, was used to study the flow past a compression ramp at Mach 2.5 and with and without a micro-ramp vortex generator (MVG) upstream. The MVG serves as a passive flow control device. The results suggested that MVGs may distinctly reduce the separation zone at the ramp corner and lower the boundary layer shape factor. New findings regarding the MVG-ramp interacting flow included the surface pressure distribution, three-dimensional structures of the re-compression shock waves, surface separation topology, and a new secondary vortex system. The formation of the momentum deficit was studied in depth. A new mechanism was observed wherein a series of vortex rings originated from the MVG-generated high shear at the boundary of the momentum deficit zone. Vortex rings strongly interact with the shock-separated flow and play an important role in the separation zone reduction.