波翼相位差对柔性翼水动力性能的影响

摘要

Under the background of a bionic propulsion system using wave energy, in this paper we investigate the influence of the phase difference between wave and foil motion on the propulsion system of a two⁃dimensional flexi⁃ble flapping foil near the wave surface under a regular wave. We applied the Reynolds⁃averaged Navier⁃Stokes ( RANS) equation solution to analyze the hydrodynamics of a flexible flapping foil with different wave phase differ⁃ences. We then compared the results with those without waves and those of rigid foil in the same working conditions. The computed results indicate that wave phase differences influence the phase angles of the hydrodynamic coeffi⁃cients, as well as their magnitude. With a favorable wave phase difference, a flexible foil can improve its thrust force and efficiency by utilizing wave energy and its ability to utilize wave energy is higher than that of a rigid foil. Wake characteristics were also analyzed, and the results show that a favorable wave phase difference can improve the gradient and continuity of the wake vortex, and thereby increase the thrust and efficiency of the flexible foil un⁃der the wave surface.%以仿生推进系统利用波浪能为背景，研究了波翼相位差对规则波下近波面二维柔性拍动翼的推进性能的影响。采用求解RANS方程的方法，计算了不同波翼相位差下柔性翼的水动力性能，并与无波情况下及相同工况下刚性翼结果进行比较。计算结果显示：波翼相位差对翼水动力系数的相位、幅值有影响，恰当波翼相位差下，柔性翼能有效利用波浪能增加自身推力及效率，且其对波浪能的利用能力高于刚性翼。尾涡分析表明，恰当的波翼相位差能够提高柔性翼尾涡梯度及其连续性，从而提高波面下柔性翼推力及效率。