鲹科鱼类中鳍相互作用对自主游动性能影响研究
STUDY ON THE INFLUENCE OF CARANGIFORM FISH MEDIAN FINS INTERACTION ON AUTONOMOUS SWIMMING PERFORMANCE
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摘要: 鱼类通过中鳍(背鳍、臀鳍和尾鳍)之间的相互作用可实现比只利用尾鳍游泳更高的推进性能, 但当前多数研究仍是基于身体尾鳍模型, 采用躯干和尾鳍摆动推进研究鱼类游泳性能和游动机理. 为了解鲹科鱼类中鳍相互作用对自主游动性能的影响, 本研究利用高精度三维激光扫描仪建立了真实的鱼体几何模型, 对具有完整中鳍的鲹科鱼类自主游动行为进行了三维数值模拟. 通过求解鱼体从静止加速到巡游状态的游动过程, 比较了不同相位差下鲹科鱼类的游泳性能, 并详细分析了鱼体尾部的涡流动力学. 结果表明: 由于背鳍和臀鳍摆动脱落的后体涡(PBV)在向后传播过程中, 会被尾鳍前缘捕获并与前缘涡(LEV)相互作用, 增强前缘涡(LEV)的强度, 从而极大提升鲹科鱼类游泳性能. 与只依靠身体尾鳍游泳模型相比, 推力最高提升了26.11%, 效率最高提升了18.15%, 游泳速度最高提升了60.14%. 本文研究揭示了鲹科鱼类中鳍间相互作用的机制, 阐明了鲹科鱼类中鳍相互作用对自主游泳性能增强的流体动力学机理, 为鲹科鱼类游泳性能与游动机理的研究提供了新的见解.Abstract: Fish can achieve higher propulsion performance through the interaction among their median fins (dorsal fin, anal fin and caudal fin) than swimming with only the caudal fin. However, most current studies are still based on the body caudal fin model, using the swinging propulsion of the trunk and caudal fin to study the swimming performance and swimming mechanism of fish. To understand the influence of median fins interaction on the autonomous swimming performance of carangiform fish, in this study, a real geometric model of the fish body was established using a high-precision three-dimensional laser scanner, and three-dimensional numerical simulation was conducted on the autonomous swimming behavior of carangiform fish with complete median fins. By solving the swimming process of the fish body accelerating from a stationary state to a cruising state, the swimming performance of the carangiform fish under different phase differences was compared, and the vortex dynamics at the tail of the fish body was analyzed in detail. The results indicate that the posterior body vortices (PBV) caused by the swinging and shedding of the dorsal and anal fins are captured by the leading edge of the tail fin and interact with the leading edge vortices (LEV) during backward propagation, enhancing the strength of the LEV and greatly improving the swimming performance of carangiform fish. Compared with the swimming model that only relies on the caudal fin and body, the thrust has increased by up to 26.11%, the efficiency has increased by up to 18.15%, and the swimming speed has increased by up to 60.14%. This paper reveals the mechanism of the carangiform fish interaction between the median fins, clarifies the hydrodynamic mechanism by which the interaction between the median fins enhances the autonomous swimming performance of carangiform fish, and provides new insights for the study of carangiform fish swimming performance and swimming mechanism.