Delay of stall for a stationary wing placed in a wake

The unsteady aerodynamics of a wing with NACA 0012 profile placed in a turbulent wake was investigated experimentally in a wind tunnel at a chord Reynolds number of 10⁵. The quasi-periodic large-scale coherent vortical structures lead to substantial lift enhancement and delay of stall, which is due to the flow separation, leading-edge vortex formation, and subsequent reattachment in a process similar to the dynamic stall of oscillating wings. There exists an optimal offset distance from the wake centreline at which the maximum lift enhancement was observed. The smaller amplitude flow oscillation at the optimal locations rather than the direct impingement at the wake centreline cause the formation of a larger separation bubble in the post-stall regime.