Force Measurements and Flow Visualization of Biomimetically Designed Manduca Sexta Class Engineered Wings

摘要

Six degree of freedom force and moment measurements were taken on the Air Force Institute of Technology's (AFIT) piezoelectrically actuated, biomimetically designed Hawk-moth, Manduca Sexta, class engineered wing, at varying amplitudes and napping frequencies. Conservative voltage amplitudes, about 50% below the maximum necessary to achieve the same total stroke angle, Φ, as its biological analog, were used to drive the wing to preserve test specimen integrity. Force balance and Particle Image Velocimetry (PIV) data was collected for both symmetric flapping. Two-dimensional PIV visualization measurements were taken transverse to the wing planform, recorded at the mid-span, for a single frequency and amplitude setting. Phase averaged velocity data was extracted from the 2-D PIV imagery at ± 1/2 and ±1 chord locations above and below the wring, and the mean velocities were calculated for four separate wing phases during the flap cycle. The mean forces developed during a flap cycle were approximated using a modification of the Rankine-Froude axial actuator disk model to calculate the transport of vertical momentum flux. This is the vertical force, thrust, produced during a static hover flight condition. Through interpolation of the vertical velocity data, it is shown thrust values calculated from the 2-D PIV measurements were within 5% of the 6-DOF force balance experiments.