FLOW-CONTROL OVER A MANEUVERING DELTA-WING AT HIGH ANGLES OF ATTACK

The possibility of delaying vortex breakdown to higher angles of attac k by employing control surfaces is studied experimentally. The effect of an apex flap is tested for fixed and dynamically pitching delta win gs. Flow visualization, surface pressure measurements, and laser-Doppl er velocimetry are employed to map out pressure, velocity, and vortici ty fields. It is found that a drooping apex Rap can delay vortex break down by an angle of 8 deg beyond the steady dow breakdown angle of att ack. The apex flap effect is equally pronounced in dynamic maneuvers.