Understanding Micro-Ramp Control of Supersonic Shock Wave Boundary Layer Interactions

Abstract

Abstract : This research investigated the potential of micro-ramp sub-boundary layer vortex generators for flow control of oblique shock boundary layer interactions (SBLIs) which is relevant to supersonic engine inlets. These novel devices can delay shock-induced separation and improve boundary layer health, thus offering the potential to reduce the bleed requirement in intakes. Micro-ramp Experiments have been conducted at Mach 2.5, to determine the nature of flow controlled by micro-ramps and investigate their ability to delay separation in a reflected shock interaction. Various ramp sizes between 30% and 90% of boundary layer thickness were investigated. The details of the vortical flow generated by such devices was identified. The general flow features were found to scale with device height and it is suggested that smaller devices need to be placed closer to the expected adverse pressure gradients. When applied to a separated oblique shock SBLI micro-ramps were not observed to eliminate flow separation, although they were shown to break up separated regions. Other performance indicators across the SBLI were also improved through the application of the devices.