Unsteady aerodynamics of deformable thin airfoils

Abstract

The paper presents a theory for the unsteady aerodynamics of deformable thin airfoils. It extends the theory developed by Theodorsen and Garrick, which is restricted to rigid body motion. Frequency-domain lift, pitching moment, and thrust expressions are derived for an airfoil undergoing harmonic oscillations and deformation in the form of the Chebychev polynomials. The first two polynomials give the rigid body motion, whereas the rest represent the deformation. The results are verified with the time-domain unsteady aerodynamic theory of Peters. Numerical results are presented for several combinations of airfoil motion, which identify various possibilities for thrust generation using a deformable airfoil.