Aeroelastic Airfoil with Free Play at Angle of Attack with Gust Excitation

Abstract

A theoretical and experimental aeroelastic study of a typical airfoil section with control surface free play for nonzero angle of attack in low subsonic flow is presented. The study includes the flutter and limit cycle oscillation behavior and also the linear and nonlinear aeroelastic responses excited by periodic gust loads. The theoretical approach uses Peters's finite state airloads model. The experimental investigation has been carried out in the Duke University wind tunnel using a rotating slotted cylinder gust generator. The theoretical and experimental results show that the self-excited aeroelastic limit cycle oscillation is sensitive to the effect of initial pitch angle. For the gust response, the effect of initial pitch angle is smaller for the plunge and pitch responses and is larger for the flap response. The fair to good quantitative agreement between theory and experiment verifies that the present analytical approach has reasonable accuracy and good computational efficiency for nonlinear aeroelastic response analysis of such systems.