The effect of wake from forward wing on performance of wing with liner leading edge and one with sinusoidal leading edge

In previous research, it has been reported that wing with sinusoidal leading edge has the effectiveness of separation control. The wing models used in previous studies were, however, limited to single wing and it wasn’t practical for actual devices with multiple wings. Then, we studied the effect of sinusoidal leading edge in the case of tandem arranged wings. To investigate the effect of wake from forward wing, we measured the fluid dynamic force on backward wing with load cells and visualized the flow around backward wing by the smoke wire technique. The experiment was conducted with a wind tunnel. The performance of the backward wing with linear leading edge was improved when the vertical gap between forward wing and backward wing, y/c, was in the range of -0.125≦y/c≦0.25. From visualization results, it was found that the improvement was caused because the wake from forward wing controlled the stall of backward wing. On the other hand, the backward wing with sinusoidal leading edge maintained the effectiveness of stall control regardless of vertical gap, presence or absence of forward wing. Therefore, the wing with sinusoidal leading edge is effective as separation control technique for devises having multiple wings like wind power generator.