Investigation of the interaction between wake and separated boundary layer at low reynolds numbers

The suction boundary layer development of typical aft-loading low pressure turbine was modeled by flat plate with proper pressure gradient. Interaction between the wake and the separated boundary layer was investigated. The effect of Reynolds number was studied and the interaction of separated region with trailing edge vortex shedding at very low Reynolds number was analyzed. The results show that at the same exit Mach number, the isentropic Mach number of the wall changes and the peak Mach number decreases with decreasing Reynolds number. The interaction of the wake and the separated region can suppress the boundary layer separation by turbulent and the calmed region produced by the breakdown of rollup vortices induced by wake in the separated boundary layer. The unsteadiness of the separated region and trailing edge vortex shedding should be paid attention in turbine design process at very low Reynolds number.