高频同相扰动信号对升沉扑翼水动力性能影响

To investigate the effect of external input sinusoidal perturbation signals on the propulsive performance and wake structure of a heaving foil, numerical simulation method was used to investigate the effect of adding high-frequency in-phase sinusoidal perturbations to the basic sinusoidal input signal of a heaving foil. Numerical calculation results show that in most cases, the introduction of perturbation increases the axial thrust, especially when the fundamental frequency is 0.50 Hz, the addition of 12 Hz perturbation drives the axial thrust to 843.5% of the original. The calculation results confirm that the heaving foil can have good propulsion efficiency only at low base frequency, and the foil propulsion efficiency tends to decrease with the increase of base frequency or perturbation frequency. Results show that when at the lowest base frequency of 0.50 Hz, with the increase of the perturbation frequency, the vortex structure starts to convert from the model without obvious vortex shedding to the 2S model at the perturbation frequency of 4 Hz;when at the base frequency of 0.75 Hz, the vortex structure converts from the 2P model to the 2S model with the increase of the perturbation frequency; when at the base frequency of 1.00, 1.25, 1.50 and 1.75 Hz, the vortex structure becomes chaotic from the 2S model with the increase of the perturbation frequency.