Development of a Device for Controlling the Leading Edge Vortices on a Delta Wing.

Abstract : Recent experimental observations have shown that a leading edge vortex on a delta wing at constant angle of attack consists of a series of discrete smaller vortices. These vortices pair, much the same as in a free shear layer. A device is proposed to modulate the shedding and the pairing of the discrete vortices by mechanically or acoustically perturbing the leading edge of a delta wing. By applying the perturbation to both leading edges, the total lift of a wing will be altered; alternatively, by using the perturbation preferentially on only one side of the wing, the rolling moment around the axis of symmetry of the aircraft is controlled. The proposed device will enable the pilot of a fighter aircraft to achieve a previously unattained degree of maneuverability. During the first phase of this research, experiments were conducted in both a water towing tank and a high speed wind tunnel. Flow visualization, fast-response velocity probe surveys, as well as force measurements were conducted to assess the performance of the proposed vortex control device and, more importantly at this early stage of the research, to understand the complex flow field under consideration. Keywords: Vortex control device; Lift control; Lift enhancement; Super-maneuverability.