The Effect of angle of attack on limit cycle oscillations for high-aspect-ratio wings

In this study, the eect of the angle of attack on the aeroelastic characteristics of high aspect ratio wing models with structural nonlinearities in unsteady subsonic aerodynamic ows is investigated. The studied wing model is a cantilever wing with ag, lag and torsion vibrations and with large de ection capability, in accordance with the Hodges-Dowell wing model. An unsteady low speed incompressible air ow is assumed to include the ow time lags. Variations of the limit cycle amplitudes and frequency with free stream velocity at dierent angle of attacks are carefully studied. For the considered model, the angle of attack has little eect on utter velocity but its eect on limit cycle amplitudes and frequency is considerable. This study shows that the limit cycle amplitudes are very sensitive to variations in angles of attack.