仿双髻鲨头部的仿生机器鱼外型设计及其流场特性

SHAPE DESIGN AND FLOW FIELD CHARACTERISTICS OF A ROBOTIC FISH IMITATING THE HEAD OF A HAMMERHEAD

近年来对海洋资源的开发利用成为了社会的研究热点,推动了国内外学者关于水下航行器各方面的研究工作.其中航行器的外形设计是研究中较为重要的一部分,直接影响其在水中行进时所表现流体性能的优劣.自然界中存在的各种鱼类以其阻力性能好等优点吸引了科研工作者广泛关注.为设计流体性能较好的航行器壳体外形,本文将目光放在了双髻鲨身上,它的头部就像一个水中翼,帮助其在海洋中灵活的游动.本文以其为仿生的对象,首先建立模型分析了3种不同双髻鲨的头部减阻效果,选定锤头双髻鲨的生物形体特征作为壳体外形特征曲线,并结合工程实际设计了一种仿生机器鱼外形,应用Ansys Mosaic技术建立三维流场结构化网格模型,对其进行Fluent仿真.随后与目前主流的翼型壳体外形和回转体航行器外形进行对比,重点研究其减阻性能.通过仿真分析得出,与上述两种常见的水下航行器相比,仿双髻鲨模型在定常流场中表现出更优秀的流体性能.本文还探究仿双髻鲨模型周围流场的特性,对于减少航行器对周围流场干扰方面和改善航行器隐蔽性方面的研究有一定的指导意义,同时也为水下航行器的设计提供新的方向.

In recent years,the exploitation and utilization of marine resources have risen to a social research highlight.In this context,domestic and overseas scholars work to promote the study on many aspects of underwater vehicles.As an important part of the research,the hull shape design of the underwater vehicles has direct relation to their underwater hydrodynamic characteristics.A variety of fishes in nature have attracted extensive attention from researchers for their good hydraulic resistance performance.In order to design a hull shape of underwater vehicle with good hydrodynamic characteristics,this paper focuses on the study of Sphyrna with a winglike head which enables their nimble swimming in oceans.This paper took Sphyrna as the bionic object,analyzed the water resistance reduction effects of three species of Sphyrna by establishing models,selected the biological shape characteristics of hammerhead shark as the reference to design the characteristic outline curve of the hull.Furthermore,a kind of hull shape of underwater vehicle has been designed according to engineering practice.Ansys Mosaic Technology was applied to establish a 3 D structured flow field mesh model,and a Fluent simulation of the model followed.Apart from that,the author compared it with the shapes of common wing-shaped hulls and rotational underwater vehicles,focusing on its resistance performance.The result of a simulation analysis shows that the Sphyrna bionic model demonstrates better hydrodynamic characteristics in a stationary flow field than those of the two kinds of common underwater vehicles.Additionally,this paper also designed a comparative experiment to explore the characteristics of the flow field around the Sphyrna bionic model,which is of great guiding significance for the study on reducing the interference of the vehicles to the surrounding flow field and improving the stealthiness of the vehicles,and also provides a new direction for the design of underwater vehicles.