仿胸鳍推进系统的水动力分析

Analysis of the hydrodynamics of a pectoral fin propulsor

针对刚性胸鳍建立了二自由度、三自由度的运动模型,同时提出了行程时间比运动模型.在此基础上,从面元法出发,根据偶极子分布与漩涡分布的等效性,发展得到非定常涡格法的理论公式,利用非定常涡格法分析刚性胸鳍的水动力性能.胸鳍的运动由静止突然加速到恒定,在每个时间步长内用定常涡格法求解附着涡的涡强.自由涡由边缘泄出,并按时间步长逐步自动生成,并考虑其强度的耗散.采用B iot-Savart定理求涡系的诱导速度,通过非定常伯努利方程导出压力计算公式,从而得到胸鳍的水动力性能.

In this paper two-degree-of-freedom and rigid pectoral fin. Also, a motion-time ratio model three-degree-of-freedom motion models were established for a was constructed. Furthermore, the theoretical expression of the unsteady vortex lattice method （UVLM） was developed from the Hess-Smith panel method by using equivalence of normal dipole and vorticity distribution. The unsteady vortex lattice method was used to analyze the hydrodynamic performance of pectoral fin motion. The pectoral fin was suddenly accelerated to constant motion from rest. In each time step we obtained the vortex strength of the pectoral fin using the vortex lattice method. The wake was formed step by step from the edge of the pectoral fin. In this process the dissipation of the wake vortex strength was taken into account. The induced velocity of the vortex system was calculated with the Biot-Savart law and the pressure on the fin was obtained from the Bernoulli equation. In the fin were obtained. way all parameters of the hydrodynamic performance of the