The effect of the Upper Vortex Flap is parametrically studied for various flap deflection angles. At small angle of attack, lift is increased for all flap deflection angles. Drag is reduced and L/D is increased, for small flap deflection angle. And for large flap deflection angle, both lift and drag are increased, when compared with the delta wing without flap.
Lift, drag, and pitching moment were measured at the free stream velocities of 25 m/sec and 40 m/sec for flap deflection angle of 30, 60, 90, 120, 150 degree with angle of attack varying from 0 to 27 degree.
Surface oil flow visualizations at 20.5 degree angle of attack for all flap deflection angles were carried out.
