Aerodynamic Active Flow Control using Hybrid, Momentum-based Actuation

The aerodynamic characteristics of a Clark-Y airfoil with a rounded trailing edge are modified

using active flow control (AFC) to enable aerodynamic control in the absence of moving control

surfaces. Using AFC, small-scale local perturbations are engendered near the airfoil surface which

lead to larger-scale changes in the flow around the airfoil. Distributed aerodynamic bleed, a form

of AFC in which a flow is driven through the airfoil interior by pressure differences between the

pressure and suction surfaces and regulated by integrated lateral louvers, is located near mid-

chord and used to reduce lift and increase drag. Blowing from fluidic jets is used at the leading

edge of the suction surface to mitigate separation at high angle of attack, leading to increased lift,

and on both surfaces near the trailing edge to form Coanda jets for varying lift bi-directionally. By

using hybrid actuation consisting of multiple forms of AFC, the aerodynamic effects can be

combined. For instance, lift can be varied bi-directionally with changes in pitching moment using

trailing edge blowing from opposite surfaces, or without altering pitching moment using

aerodynamic bleed with leading edge blowing.