Aero-Effected Flight Control Using Distributed Active Bleed

Abstract : A novel, scalable approach to aero-effected flight control of lifting surfaces using distributed active bleed was investigated experimentally and theoretically. Aerodynamic control is achieved by large-area surface bleed of air that is driven by the pressure differences in flight and is regulated by low-power surface-integrated louver actuators. The joint numerical-experimental investigation focused on the flow mechanisms of the interaction between the bleed and the cross flow and aerodynamic effects of unsteady bleed on a 2-D wing model. Particular emphasis was placed on the generation and regulation of vorticity concentrations that alter the wing s apparent aerodynamic shape and thereby its aerodynamic performance over a range of (static) angles of attack, and under time-periodic pitch oscillations. Wind tunnel investigations of the mechanisms of the time-dependent interactions between the bleed and cross flows used a 2-D Clark-Y model integrated with addressable arrays of piezoelectric louvers for regulating leading and trailing edge bleed. The resulting time-dependent forces and moment were measured over a wide range of angles of attack from pre- to post-stall using load cells, and the induced changes in surface vorticity concentrations were measured using PIV.