Aerodynamic Work Based on an Extended Theodorsen Function for an Airfoil with a Wake

Abstract

Extended lift and moment, based on an extended Theodorsen function for arbitrary and constant convection velocity of wake vortices, are converted to aerodynamic work. Pure pitching oscillations, pure translational oscillations and their combinations are considered. Decrease in convection velocity of wake vortices yields an increase in aerodynamic work, thus destabilizing airfoil oscillations. Some of the available wind-tunnel data support the present theoretical predictions.