基于非定常薄翼理论的鱼类游动系留与自推进模型性能比较
Performance comparison of tethered and self-propelled models of fish locomotion using unsteady thin airfoil theory
- Virginia Tech（弗吉尼亚理工大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究使用非定常面元法比较系留与自推进鳍的游动性能，发现优化系留游动体的运动学策略并不一定适用于自推进游动体。
AI中文摘要：
过去几十年中，大量实验和计算研究致力于理解鱼类的游动性能，并确定游动鱼类或仿鱼机器人的最优运动学策略。许多研究将游动体建模为“系留”条件，即游动体固定不动，同时受到均匀来流作用，其性能通过功率消耗、推力产生和效率来量化。然而，系留游动体的动力学与自推进游动体不同，后者的性能最好通过其在静止流体中的稳态游动速度及其效率来衡量。系留游动体研究得出的结论能否直接应用于自由游动体，仍是一个悬而未决的问题。在本研究中，我们使用非定常面元法，系统比较了系留鳍和附着在虚拟阻力产生体上的自推进鳍的游动性能，以探究在一组规定的运动学参数下它们的性能如何变化。在将数值模型与先前的实验结果进行验证后，我们展示了俯仰振幅、升沉振幅以及它们之间的相位偏移如何影响系留情况下的效率和推力产生，以及它们如何影响自推进情况下的速度和效率。我们发现，优化系留游动体性能的运动学策略不一定能优化自推进游动体的性能。
英文摘要：
Numerous experimental and computational studies have been conducted in the past few decades to understand the swimming performance of fish, and to identify the optimal kinematic strategies for a swimming fish or fish-like robot. Many of these studies model the swimmer in a `tethered' condition, in which the swimmer is held fixed while it is subjected to a free stream. Its performance is then quantified using power expenditure, thrust generation, and efficiency. However, the dynamics of a tethered swimmer are different from those of a self-propelled swimmer, whose performance is best measured using its steady-state swimming speed in still fluid and its efficiency. It is an open question whether the conclusions drawn from studies of tethered swimmers can be directly applied to free swimmers. In this study, we use an unsteady panel method to systematically compare the swimming performance of a tethered fin and that of a self-propelled fin attached to a virtual drag-producing body to investigate how their performance varies over a set of prescribed kinematics. After validating the numerical model against previous experimental results, we show how the pitch amplitude, heave amplitude and the phase offset between them affect the efficiency and thrust generation in the tethered case, and how they affect the speed and efficiency in the self-propelled case. We find that the kinematic strategies that optimize the performance of a tethered swimmer do not necessarily optimize the performance of a self-propelled swimmer.
