Aerodynamics and Vortex Flowfield of a Slender Delta Wing With Apex Flap and Tip Flap

Abstract

The effect of apex flap and tip flap, deflected both independently and jointly, on the vortex flow and lift generation of a 65 deg-sweep delta wing was investigated experimentally. The drooped apex flap produced a higher lift at medium-to-high angle of attack regime and also a delayed stall. The anhedral (introduced by the downward tip flap) generally promoted lift increment, whereas dihedral had the opposite effect. Meanwhile, the joint apex and tip flap deflection gave a delayed leading-edge vortex (LEV) breakdown and an enhanced lift. The LEVs were generally drawn closer to the wing upper surface, while being pushed further away from the wing centerline by the application of apex flap and tip flap. The flap also modified the vorticity distribution in the LEV; the bursting behavior was, however, not affected. Dye-injection flow visualization and particle image velocimetry (PIV) measurements of the vortex flow were also discussed.