Experiments in Transverse Gust Mitigation Using Open-Loop Pitch Maneuvers

This paper presents three open-loop pitch maneuvers with the objective of mitigating the lift transient during large-amplitude transverse wing-gust encounters. In the first maneuver, the wing’s instantaneous geometric angle of attack opposes the effective angle of attack induced by the gust. In the second maneuver, the analytical lift result from an unsteady aerodynamic model based on the work of Wagner and Küssner sums to zero. In the third maneuver, the wing’s pitch kinematics are obtained from closed-loop control simulations in an unsteady discrete vortex model (DVM). The open-loop pitch maneuvers were experimentally implemented for different gust ratios, and force and flowfield measurements were collected. The lift coefficient as well as shed vortex circulation time histories of all the cases are compared to identify the flow physics responsible for lift attenuation. In addition, the flowfield’s vorticity, vector fields, and streamlines of select cases are presented and analyzed. Finally, the DVM-simulated flow fields are compared to experimental flowfield measurements to assess its accuracy and viability for maneuver design.