Hydrodynamic Performance of Efficiency Transition Point of Forked Caudal Fins

• Published in: 水下无人系统学报 Vol. 32; no. 1; pp. 114 - 123
• Main Authors: Zhongying XIONG, Yueyao LIU
• Format: Journal Article
• Language: Chinese
• Published: Science Press (China) 01.02.2024
• Subjects: biomimetic robotic fish; forked caudal fin; hydrodynamic performance; vortex
• ISSN: 2096-3920
• DOI: 10.11993/j.issn.2096-3920.2023-0066

Thunniform fish has high swimming speed and swimming efficiency and thus becomes the ideal biological prototype of bionic robotic fish. In order to study the hydrodynamic characteristics of the efficiency transition point of the forked caudal fins of thunniform fish, the source terms influencing thrust and power consumption were mainly analyzed. The caudal fin model used the same surface area, aspect ratio, and fork length. To unify the metrics about the fin shape, the sweep angle was used to represent the structure for the forked caudal fins in this paper. It is found that the increase in the sweep angle attenuates the available area of the caudal fin of the thunniform fish, resulting in a lower reaction force to push the fluid downstream when the caudal fin swings. As a result, the thrust of the caudal fin decreases. Additionally, the rise in the sweep angle also triggers the enhancement of the strength and the development of the leading-edge vortex, thereby inducing greater vortex-augmented thrusts. Howeve