基于蝠鲼的仿生四鳍游动结构设计及其流体仿真

Biomimetic Quadrifin Locomotion Structure Design and Fluid Simulation Based on Batoid Fish

摘要: 设计一款仿生蝠鲼水下机器，用于收集海洋漂浮物垃圾，重点研究了实现仿生蝠鲼推进机制的胸鳍这一动力系统。应用生物力学和运动捕捉法，研究了蝠鲼的肌肉运动、鳍条结构及水流动力学特性等游动机理，识别出摆动频率ω、幅度A和相位φ等胸鳍摆动的关键特征，建立了仿生蝠鲼胸鳍的摆动函数。设计并加工出仿生蝠鲼样机，完成了直线游速试验，定量评估了30˚、45˚和60˚三种不同相位差对仿生蝠鲼直线游动速度的影响，确定了水流扰动仿真模型中初始流速这一边界条件。完成了水下环境中水流扰动及其对鳍面压力影响的流体动力学仿真，获得了不同相位时鳍面的流线云图。研究结果表明：在前后鳍板摆动频率一致的情况下，30˚相位差能产生最小的水流扰动，鳍面压力分布均匀，游速达到最快，可满足常规海面流速下的垃圾收集要求。

Abstract: A bionic manta ray underwater machine was designed to collect floating debris in the ocean. The pectoral fin power system, which realizes the bionic manta ray propulsion mechanism, was studied. Using biomechanics and motion capture method, the motion mechanism of manta ray such as muscle movement, fin structure and hydrodynamic characteristics was studied. The key characteristics of pectoral fin swing such as frequency ω, amplitude A and phase φ were identified, and the pectoral fin swing function of bionic manta ray was established. The bionic manta ray prototype was designed and processed, the linear swimming speed test was completed, and the influence of three different phase differences of 30˚, 45˚ and 60˚ on the linear swimming speed of the bionic Manta ray was quantitatively evaluated, and the boundary condition of the initial flow rate in the current disturbance simulation model was determined. The hydrodynamic simulation of flow disturbance and its influence on fin surface pressure in underwater environment is completed, and the flow line cloud image of fin surface in different phases is obtained. The results show that under the condition of the same swing frequency of the front and rear fins, the 30° phase difference can produce the smallest flow disturbance, the fin surface pressure distribution is uniform, and the swimming speed is the fastest, which can meet the requirements of garbage collection under the conventional sea surface velocity.