Fluidic Variation of Aerodynamic Loads on a 3-D Wing using Distributed Active Bleed

The aerodynamic loads on a representative 3-D wing model with a trailing edge flap are controlled in wind tunnel experiments using distributed air bleed that is driven through arrays of ports in the airfoil surface by pressure differences between the pressure and suction surfaces and is regulated by low-power, surface-integrated louvers for improved temporal response compared to conventional control. Interaction between the bleed and the local cross flow over the surface induces large-scale changes in the global flow field which lead to modification of the aerodynamic loads without varying the angle of attack.The aerodynamic load variation occurs on the convective timescale of the flow, which is significantly faster than the movement of conventional aerodynamic control surfaces. The present research program focuses on the elucidation of the receptivity of the flow over a 3-D wing model to manipulation by the bleed flow and the flow mechanisms that link these interactions to controlled variations in the global aerodynamic loads. High-resolution stereo particle image velocimetry measurements are used to characterize the variation of the distribution of streamwise vorticity in the wake, and the corresponding variation of the spanwise loading of the wing.