Unsteady Stall Control Using Dynamically Deforming Airfoils

Abstract

An experiment documenting the compressible flow over a dynamically deforming airfoil is presented. This airfoil, which has a leading-edge radius that can be dynamically changed, was tested at various deformation rates for fixed airfoil angle of attack. Selected leading-edge shapes were also tested during airfoil oscillation. These tests show that for a range of Mach numbers observed on the retreating blades of helicopter rotors the dynamic stall vortex can be avoided by a judicious variation of leading-edge curvature.