尾鳍摆动驱动仿生机器鱼的水动力性能仿真分析

Simulation analysis of hydrodynamic performance of bionic robotic fish driven by caudal fin swing

本文以鲣鱼为仿生对象,根据鱼体形态特征建立单关节和三关节尾鳍机器鱼三维模型和二维仿真模型,基于大幅值细长体理论,建立了两种不同尾鳍摆动形式机器鱼的运动学模型,并根据运动方程编写UDF程序,采用动网格技术定义动边界条件,实现了机器鱼自主游动,并模拟计算了两种尾鳍摆动模式的机器鱼在特定流场下的流场压力及鱼体受力等水动力性能。结果表明,与单关节尾鳍机器鱼相比,三关节尾鳍机器鱼自主游动时流场最大压差减小了13.3%,侧向力幅值减小了52.0%,表明三关节尾鳍机器鱼巡游时更加符合真实鱼游动姿态,具有较大的推进力和较优的平衡性。

By taking bonito as the bionic object,the three-dimensional and two-dimensional simulation models of single-joint and three-joint caudal fin robotic fish were established according to the morphological characteristics of the fish body.Based on the large-amplitude elongated-body theory,the kinematic models of two different swing forms of caudal fin were established,and the UDF program was written according to the motion equation.The dynamic grid technology was adopted to define the dynamic boundary conditions,which realized the autonomous swimming of the robotic fish,and the hydrodynamic performance such as the pressure of flow field and the force on the fish body were calculated.The results show that,compared with the single-joint caudal fin robotic fish,the maximum differential pressure of the flow field of three-joint caudal fin robotic fish is decreased by 13.3%,and the amplitude of lateral force is 52%smaller than that of the single-joint caudal fin robotic fish,which indicates that the three-joint caudal fin robotic fish is more similar to the real fish’s swimming posture,and has greater propulsion force and balance performance.