Transient Response of a Single Degree-of-Freedom Wing at High Angle-of-Attack

Abstract

A torsional spring was added to the leading edge of a free-to-pivot rectangular aspect ratio four flat plate wing to observe the effect of discrete compliance on the wing force and angle-of-attack response at a Reynolds number of 20,000. The spring stiffness was varied between a completely free-to-pivot wing and a rigidly attached wing, with two cases in between. The addition of springs was found to force the wing at a higher angle of attack than the free-to-pivot case, and thus increase force production. The wing acceleration distance and Reynolds number were also varied. The Reynolds number had a significant effect on the steady-state forces due to variation in the dynamic pressure, but acceleration had little impact. A low-order model of the wing dynamics based on thin airfoil theory was discussed and applied to the specified wing kinematics. The results of this model showed promising agreement during the transient and reasonable success once the wing reached steady state, paving the way for better design and control of flapping-wing micro air vehicles.