非正弦俯仰运动对扑翼自主推进的影响

Numerical simulation was used to couple the fluid dynamic equation and the flapping wing motion equation to establish a flapping-fluid coupling self-propulsion computation model. The longitudinal and lateral self-propulsion of a flapping wing under non-sinusoidal pitching motion was numerically simulated, and the influences of different motion waveforms and pitching frequencies in still water on self-propulsion speed, self-propulsion efficiency and flow structure were studied. Results show that the non-sinusoidal waveform adjustment parameter K and the pitch frequency have a great influence on the forward speed and forward distance of self-propulsion. Increasing K or frequency can increase the average forward speed, forward distance and lateral displacement. The maximum average speed is obtained in the square wave of K=2.5, which is 70.3% higher than that of sine wave motion. The efficiency of self-propulsion and the energy utilization rate continue to increase with the decrease of K, the propulsion efficiency is high at high frequencies, and the energy utilization rate at low frequencies is high.