基于锦鲤BCF摆动推进特性分析

以锦鲤为仿生对象，研究躯干和尾鳍的摆动推进特性。根据鱼体形态特征建立仿生鱼几何模型，并根据鱼体躯干和尾鳍的摆动姿态，分别建立不同的运动学模型，进而采用动网格技术并编写控制鱼体的UDF程序，对仿生鱼在被两种控制方程的驱动下的运动状态进行数值模拟，研究不同的运动频率、摆动幅度、来流速度对仿生鱼游动速度、加速度、位移及其压力分布的影响，揭示两种控制方程下仿生鱼摆动的推进性能特性。结果表明：在两种控制方程的驱动下，无论运动频率怎样变化，仿生鱼达到稳定状态时间相同，相同周期内游动距离相近；当摆动幅度为30°时，仿生鱼达到稳态时间最短，且波动相对较小，是最佳幅度；来流速度低于0.1时，可以在流场中稳定游动。且该模型在稳定游动状态下，高压低压分布在尾鳍两端，推动鱼体前进，与实际相符合。

Based on the analysis of the oscillating propulsion characteristics of koi BCF

Koi carp is used as a bionic object to study the swinging propulsion characteristics of its torso and tail fin. According to the morphological characteristics of the fish, the geometric model of the bionic fish is established. Different kinematic models are established according to the swing posture of the torso and caudal fin. Then, using the dynamic grid technology and writing the UDF program to control the fish body, the movement state of the bionic fish driven by the two governing equations was simulated numerically. The effects of different motion frequency, swing amplitude and incoming flow velocity on swimming speed, acceleration, displacement and pressure distribution of bionic fish are studied, and the propulsive performance characteristics of bionic fish swing under two governing equations are revealed. The results show that, driven by the two governing equations, no matter how the movement frequency changes, the biomimetic fish reaches the steady state at the same time, and the swimming distance in the same period is similar. When the oscillation amplitude was 30°, the bionic fish reached the steady state in the shortest time, and the fluctuation was relatively small, which was the best amplitude. When the incoming flow velocity is lower than 0.1, it can swim stably in the flow field. In the stable swimming state, the high pressure and low pressure are distributed at both ends of the caudal fin to push the fish forward, which is consistent with the reality.