Effect of gurney flaps on a nonslender delta wing during large-amplitude and high-frequency dynamic pitching

The flow control effect of Gurney flaps on 50 degrees swept delta wings during large-amplitude and high-frequency pitching were investigated both experimentally and numerically. Both force and velocity measurements were conducted and compared with the numerical simulation results. The lift hysteresis was found to be significantly affected by the Gurney flaps. It was found that the leading-edge Gurney flap (LG) acts to redistribute the vorticity over the suction surface of the wing during the upstroke process. The formation and development of the leadingedge vortex (LEV) on the suction surface was delayed by the LG, which was accompanied by enhancement of the lift at high angles of attack. The lower surface pressure can be altered with the flow velocity being slowed down by the trailing-edge Gurney flap (TG), which improves overall lift performance of the pitching wing at small to moderate angles of attack.