仿生机器鱼外形设计及流场阻力数值分析

Numerical analysis of the shape design and flow field resistance of the bionic robot fish

摘要:

在机器鱼设计过程中,鱼体、尾鳍的外形设计十分重要。为了研究流体阻力更小、推进效率更高的全鱼外形,本文以金枪鱼、海豚和旗鱼为仿生对象,建立了三种不同的机器鱼模型,运用动网格技术定义了边界条件,并用数值方法分析了三种模型在流场中的速度、鱼体受力等水动力性能。结果表明,旗鱼模型游动性能最好,相比于金枪鱼与海豚模型,行进过程中受到的阻力更小,且通过斯特罗哈尔数比较旗鱼模型推进效率更高；另一方面,新月鳍仿生鱼游动速度最高,是八字鳍仿生鱼的2.2倍左右；因此,旗鱼新月鳍机器鱼具有更好的游动性能。计算结果对减小机器鱼流体阻力,提高其推进效率提供了较好的参考价值。

关键词:仿生机器鱼;静水阻力;外形;推进效率;数值分析;

Abstract:

In the process of robotic fish design, the shape design of fish body and tail fin is very important. In order to study the shape of the whole fish with less fluid resistance and higher propulsion efficiency, this paper took tuna, dolphin and sailfish as bionic objects, established three different robotic fish models, defined the boundary conditions by using dynamic mesh technology, and analyzed the hydrodynamic performances such as velocity and fish body force of the three models in the flow field by numerical methods. The results show that the sailfish model has the best swimming performance, and the drag force during travelling is smaller than that of the tuna and dolphin models, and the propulsion efficiency of the sailfish model is higher by comparing with the Strouhal. On the other hand, the crescent-fin bionic fish has the highest swimming speed, which is about 2.2 times higher than the octagonal-fin bionic fish; Therefore, sailfish crescent-finned robotic fish has better swimming performance. The calculation results provide a good reference value for reducing the fluid resistance of the machine fish and improving its propulsion efficiency.

Key words:bionic robotic fish; hydrostatic drag; shape; propulsive efficiency; numerical analysis.