Experimental Research on a Novel Design of Variable Area Caudal Fin

Abstract:

Caudal fin has fascinated researchers for decades for their great role in fish swimming, and researchers have developed lots of designs of caudal fin to achieve high efficiency and speed propulsion. This paper presents a novel design of variable area caudal fin. A “window” which can rotate freely is designed in the middle of the fin and it can be opened by the fluid force and closed by a simple mechanism. By closing or opening the “window”, the caudal fin can vary its area dynamically in the out-stroke and in-stroke in its motion. Four modes to control the “window” in the pitching motion is then presented, their hydrodynamic forces including thrust force, lateral force and lift force are studied. It is found out that the variable area fin model can indeed improve the propulsion performance compared with the traditional fin, and the mode of closing the “window” in the out-stroke and opening the “window” in the in-stroke can generate the largest thrust force for our model than the other modes. Moreover, experiments about various kinematic parameters with different modes are conducted, it is found out different modes behave quite different with same pitching frequency and amplitude, and its propulsive performance is highly depend on the kinematic parameters. The variable area caudal fin model casts an inspiration for the novel design of underwater propulsive mechanism and the results will be useful for the propulsion study of underwater bio-mimetic vehicles.

• Periodical: Applied Mechanics and Materials (Volume 461)
• Pages: 206-212
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.461.206
• Online since: November 2013
• Authors: Bo Liu, Lei Wang, Bu Yao Chen, Feng Hua Qin, Shi Wu Zhang
• Keywords: Caudal Fin, Hydrodynamic Forces, Variable Area

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