Experimental and numerical analysis for influence of the caudal fin shape on the biomimetic propulsion performance

This paper presents a comprehensive study on the effects of the caudal fin shape on the biomimetic propulsion performance of a harmonically heaving and pitching caudal fin. A propulsion system was designed and a series of hydrodynamic experiments for three caudal fin shapes (the whale caudal fin, the dolphin caudal fin, and the tuna caudal fin) were performed. Then numerical simulations based on RANS equations were taken. Both computational and experimental results indicate that the tuna caudal fin produces the highest efficiency. However the mean thrust coefficient of the tuna caudal fin is the smallest. It is found that although the mean thrust coefficient for the tuna caudal fin is not large, input power of the tuna caudal fin is also quite small.