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自然界中鱼类尾鳍形状各种各样，但前体大部分都是扁平的椭圆形状. 该文研究了不同形状 的前体对尾鳍推进的影响. 尾鳍统一采用月牙形状; 前体采用了两种模型： A-鱼类扁平椭圆形状和B-潜艇水滴回转体形状. 通过以Strouhal数为控制参数的FLUENT数 值模拟，发现前体形状对于尾鳍的静止状态和运动状态有不同的作用，采用模型A的前体形 状更有利于长时间巡游，故鱼类采用模型A这种前体形状是自然界优胜劣汰的进化必然选择.

THE NUMERICAL STUDY OF INFLUENCE OF BODY SHAPE ON CARANGIFORM

The carangiform propulsion has been paid much attention in recent years. In nature, the fish may have many kinds of tail shape, but only a few body shapes. This paper studies the influence of the body shape on the carangiform propulsion. Two body models are used in numerical simulation: model A, the fish normal body shape; model B, the submarine shape. The tail takes a crescent shape. The strouhal number ($St$) is chosen as the main parameter, and the combined translational-rotational oscillations are taken as the motion of tail. The hydrodynamical force is calculated by the software FLUENT. The results show that the body shape does affect the carangiform propulsion, the fish body shape is beneficial to cruising as a result of the nature evolutional selection.