鱼类推进性能的数值计算

本文采用统一的三维波动板位势流模型,在文1]和2]的基础上建立了鱼类最佳游动方式理论。通过大量的数值计算,对各种鲹科模式游鱼的尾鳍推进进行了分析,并结合动物学的知识讨论了鱼类尾鳍的形态适应,用本文理论结合观测数据对鳟鱼的推进力进行了估算,计算结果和实际测量值基本一致。

NUMERICAL CALCULATION OF PROPULSIVE CHARACTERISTIC OF FISH'S SWIMMING

Based on the unified three-dimensional waving plate model, an optimum motion theory is developed in this paper. The caudal fin propulsion of fish using carangiform mode is discussed, and the morphological adaptation of caudal fin is tentatively elucidated. When the caudal fin is evaluated with middle aspect ratio, the theoretical analysis shows that good tail shape should be similar to a triangle with adequately rearward or forward slanted trailing edge, and effective tail undulations should have their lateral amplitude increased mainly in the narrow necking region, immediately anterior to the caudal fin, to a large and approximately uniform value over the fin itself. This is confirmed by observations. Fish with good drag-reducing devices are also examined. The important morphological adaptation is that their caudal fins are developed to arrow-like shape, typical to the configuration of carangiform swimmers. Using observation data and theoresi-cal methods, the swimming performance of a trout is estimated, giving satisfactory results.