Active flow control implementation for mitigating outer wing flow separation

The effect of Active Flow Control (AFC) implemented on outer part of the 3D high-lift configuration that consists of swept-back (by 25°) wing with flap fixed at 20°, slat and wing tip was investigated through numerical simulations (CFD) and experimental tests (wind tunnel). Steady blowing and steady suction were compared by numerical simulations, indicating that both AFC methods are capable to postpone the stall angle of the wingtip. However, AFC based on steady suction shows to be more efficient as it requires significantly lower velocity magnitude of only 20% what is needed for steady blowing. In parallel and to validate the numerical findings, an experiment using steady suction through was conducted at TAU wind tunnel. The experimental study shows that the suction, applied at the sensitive locations identified by CFD, can delay stall, prevent separation and increase the wing tip performance whenever the separation occurs not on the entire wingtip surface. Due to the large size of the model and the significant associated blockage, the numerical study is performed for both free-air conditions and with tunnel walls interference.