Analysis of hydrodynamic characteristics of grass carp Ctenopharyngodon idellus juveniles under free-swimming status based on Particle Image Velocimetry (PIV)
YANG Guodang, HU Xiao*, ZHANG Ben, LONG Zeyu, ZAHNG Yongnian, SHI Xiaotao
College of Water Resources and Environment, Hubei International Science and Technology Cooperation Base of Fish Passage, Three Gorges University, Yichang 443002, China
Abstract: In order to investigate the mechanisms of propulsion formation and high-efficiency propulsive mode for grass carp Ctenopharyngodonidellus juveniles under free-swimming status, the force characteristics and propulsive efficiency of grass carp juveniles with body length of 4-10 cm were measured under three swimming models including straight-line swimming, turning and backward swimming in the still water in a 0.1 m water depth trough with 20-30 μm diameter hollow glass beads and a high-speed camera by technique of Particle Image Velocimetry (PIV) combined with the vorticity theory. The results showed that the juveniles mainly depended on the positive vortices gathered in the area of tail part to generate forward thrust when it swam in straight line and in turning status, with conversion rate of 73% corresponding thrust in tail part, while the juveniles mainly depended on the reverse force generated by the negative vortices gathered in the pectoral fin to push the fish forward under the status of backward swimming. The test data indicated that the juveniles in straight-line swimming status had the maximal propulsive efficiency of 83%, followed in the swimming status of turning and backward, accounting for 74% and 65% of the maximum propulsive efficiency, respectively, when the deflection angle of head varied in the range of 9°-10°. The findings confirme that the positive vortex gathered in the tail is the main source of forward thrust of the juveniles, and that the smaller head deflection angle is more beneficial to the efficient propulsion of the juveniles, and that the smaller deflection angle is conducive to higher propulsion efficiency for the juveniles.
杨国党, 胡晓, 张奔, 龙泽宇, 张永年, 石小涛. 基于粒子图像测速技术(PIV)的自由游泳草鱼动力学特征分析[J]. 大连海洋大学学报, 2021, 36(5): 833-841.
YANG Guodang, HU Xiao, ZHANG Ben, LONG Zeyu, ZAHNG Yongnian, SHI Xiaotao. Analysis of hydrodynamic characteristics of grass carp Ctenopharyngodon idellus juveniles under free-swimming status based on Particle Image Velocimetry (PIV). Journal of Dalian Ocean University, 2021, 36(5): 833-841.
2021, Vol. 36 
