Tomographic-PIV investigation of the 3D Separation behaviour of a micro-ramp controlled SWBLI

Micro-ramp vortex generators (or micro-ramps) have gained popularity as promising alternatives to boundary layer bleed for high speed flow-control applications. Micro-ramps generate a counter-rotating vortex pair which leads to a more separation resistant boundary layer. Furthermore, they modulate the size of the shock induced separation bubble along the span such that individual cells of three-dimensional separation are formed.
In the current study, the highly three-dimensional nature of such a micro-ramp controlled SWBLI is visualized by using tomographic-PIV. The 3D mean flow field of the interaction is presented, while the 3D separation behaviour is further characterized by the separation probability of the interaction Psep at different wall-parallel planes. The largest reduction in Psep occurs along the micro-ramp centreline where separation is basically eliminated. Additionally, it is found that the total volume of separation is decreased by 70% when compared to an uncontrolled SWBLI.