Computational modelling and analysis of the hydrodynamics of a highly deformable fish pectoral fin
Computational modelling and analysis of the hydrodynamics of a highly deformable fish pectoral fin
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DOI：
10.1017/s0022112009992941
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发表时间：
2010-02-25
影响因子：
3.7
通讯作者：
Lauder, G. V.
中科院分区：
文献类型：
--
作者：
Dong, H.;Bozkurttas, M.;Lauder, G. V.
采用数值模拟方法研究了蓝鳃翻车鱼胸鳍在稳定向前运动过程中的流动。模拟是为了与Lauder等人的实验相匹配。Biomim。， vol. 1, 2006, p. S25)，并且从模拟得到的结果补充了实验分析。本文的重点是对胸鳍推进性能的定量表征，胸鳍在其行程中经历了显著的变形。这包括对推力产生机制的详细分析，以及它们与涡动力学和其他流动特征的联系。仿真结果表明，鱼鳍采用由主动和被动鳍变形驱动的复杂鳍步，具有较高的推进性能。通过将涡流动力学和鳍的运动学与鳍上的力的表面分布联系起来，发现在外展过程中，鳍的运动使尖端或鳍经历一个复杂的三维扑动运动，产生一个强大而持久的附着尖端涡。这个尖端涡与冲程外展阶段的大部分推力产生有关。在内收阶段，鳍的运动类似于“划水”。与刚性扑翼箔进行比较，以提供对鱼鳍卓越性能的见解，并从功能形态学的角度解释力的产生。
Numerical simulations are used to investigate the flow associated with a bluegill sunfish (Lepomis macrochirus) pectoral fin during steady forward motion. The simulations are intended to match the experiments of Lauder et al. (Bioinsp. Biomim., vol. 1, 2006, p. S25), and the results obtained from the simulations complement the experimental analysis. The focus of the current paper is on the quantitative characterization of the propulsive performance of the pectoral fin, which undergoes significant deformation during its stroke. This includes a detailed analysis or the thrust production mechanisms as well as their connection to the vortex dynamics and other flow features. The simulations indicate that the fish fin produces high propulsive performance by employing a complex fin gait driven by active and passive fin deformation. By connecting the vortex dynamics and fin kinematics with the surface distribution of the force on the fin, it is found that during abduction, the fin moves such that the tip or the fin undergoes a complex, three-dimensional flapping motion that produces a strong and long-lasting, attached tip vortex. This tip vortex is associated with most of the thrust production during the abduction phase of the stroke. During the adduction phase, the fin motion is similar to a 'paddling' stroke. Comparisons are made with rigid flapping foils to provide insights into the remarkable performance of the fish fin and to interpret the force production from the viewpoint of functional morphology.