The wavelength of undulatory kinematics of fish is an important parameter to determine their hydrodynamic performance. This study focuses on numerical examination of this feature by reconstructing the real physiological model and kinematics of steadily swimming Jack Fish. We perform three-dimensional numerical simulations for flows over these models composed of the trunk, and dorsal, anal, and caudal fins. Moreover, we prescribe the carangiform-like motion for its undulation for a range of wavelengths. Undulation with larger wavelengths improves the hydrodynamic performance of the carangiform swimmer in terms of better thrust production by the caudal fin, lower drag production on the trunk, and reduced power consumption by the trunk. This coincides with the formation of stronger posterior body vortices and leading-edge vortices with more circulation on the caudal fin. The real kinematics of Jack Fish surpasses the performance of those with prescribed motion owing to the flexibility of the caudal fin.

中文翻译：

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更大的波长适合carangiform游泳者的流体动力学

鱼的波动运动学波长是决定其水动力性能的重要参数。这项研究的重点是通过重建稳定游泳的杰克鱼的真实生理模型和运动学来对该特征进行数值检查。我们对由躯干、背鳍、肛鳍和尾鳍组成的这些模型的流动进行三维数值模拟。此外，我们为一系列波长的波动规定了类似carangiform的运动。在尾鳍产生更好的推力、躯干上较低的阻力产生以及躯干功耗降低方面，较大波长的波动提高了角状游泳者的水动力性能。这与在尾鳍上形成更强的后部涡旋和前缘涡旋相吻合。由于尾鳍的灵活性，Jack Fish 的真实运动学性能超过了那些具有规定运动的性能。