Numerical simulation of the hydrodynamics of self-propelled fish swimming
-
摘要: 通过对推力和阻力进行重新定义, 从根本上解决了鱼游研究中推力和阻力无法区分的难题.在此基础上, 利用自适应网格下的ghost-cell浸没边界方法, 模拟了鱼类以鲹科模式在黏性流体(309 \le Re \le 14\,581)和无黏流体 (相当于雷诺数无穷大情形)中的二维自主游动.结果表明: (1) Strouhal数随雷诺数增大而减小,当雷诺数趋向于无穷时, Strouhal数趋向于0.25; (2)在所有雷诺数情况下, 推力主要来源于压力分量; 当Re<3000时, 阻力的压力分量小于黏性力分量, 而当Re>3000, 二者的关系就会反过来; (3)推进效率随着雷诺数的增大而增大,当雷诺数趋向于无穷大时, 推进效率最高可以达到70%, 说明鲹科模式适用于较高雷诺数下的游动.
-
关键词:
- 鲹科模式
Abstract: Based on a novel method of force analysis, the thrust anddrag forces of self-propelled fish are redefined, and the difficulty indistinguish the thrust and drag in fish swimming is overcome. Then, anadaptive ghost-cell immersed boundary method is used to simulate the 2Dself-propelled carangiform swimming. Simulation cases are carried out forReynolds number in the rang of 309 \le Re \le 14581 (viscous flow) andRe=\infty (inviscid flow). The results show that: (1) The Strouhal numberdecreases with increasing the Reynolds number. If the Reynolds number tendstowards infinite, the Strouhal number approaches 0.25; (2) For all Reynoldsnumber, the main part of the thrust is the pressure component. The viscouspart of the drag is larger than the pressure part when Re<3000, while therelationship will be reversed when Re>3000; (3) The thrust efficiencyincreases with increasing the Reynolds number and the maximum efficiency isabout 70%. The result show that the carangiform swimming rule suit thehigh Reynolds situation.-
Key words:
- carangiform swimmer
-
点击查看大图
计量
- 文章访问数: 3801
- HTML全文浏览量: 32
- PDF下载量: 1603
- 被引次数: 0
下载:
