An experimental investigation on unsteady boundary layer behaviors of the suction surface of an ultra-high-lift low pressure turbine profile under periodically unsteady wakes was conducted with the help of surface-mounted hot film

and the influence of the wake-boundary layer interaction on the boundary layer separation

transition and reattachment was analyzed in detail with space-time (S-T) diagrams of quasi-wall shear stress and statistical parameters.The experimental results show that the wake has a significant influence on the boundary layer of turbine profile and the separation has been remarkably suppressed despite the larger separation bubble on the suction surface of ultra-high-lift profile at low Reynolds number.