Vortex-wake interactions of a flapping foil that models animal swimming and flight
Vortex-wake interactions of a flapping foil that models animal swimming and flight
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DOI：
10.1242/jeb.006155
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发表时间：
2008-01-15
影响因子：
2.8
通讯作者：
van Leeuwen, Johan L.
中科院分区：
文献类型：
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作者：
Lentink, David;Muijres, Florian T.;van Leeuwen, Johan L.
许多游泳和飞行动物的流体动力学涉及涡流的产生和脱落到尾流中。在这里，我们研究了肥皂膜隧道中简单的二维扑动箔产生的类似涡流的动力学。扑动的箔片模拟了向前运动的动物翅膀、鳍或尾巴。由箔片引起的涡流与皂膜（由此产生的）厚度变化相关。我们通过光衍射将这些厚度变化可视化，并用数字高速相机记录下来。这种设置使我们能够研究水翼运动学对涡流-尾流相互作用的影响。我们以恒定的无量纲扑动幅度 (A*=1.5) 和几何攻角幅度 (A(alpha,geo)= 15 度）改变箔的无量纲波长 (l*=4-24)。相应的雷诺数约为 1000。这些值与动物游泳和飞行有关。我们发现箔在低无量纲波长 (l*
The fluid dynamics of many swimming and flying animals involves the generation and shedding of vortices into the wake. Here we studied the dynamics of similar vortices shed by a simple two-dimensional flapping foil in a soap-film tunnel. The flapping foil models an animal wing, fin or tail in forward locomotion. The vortical flow induced by the foil is correlated to (the resulting) thickness variations in the soap film. We visualized these thickness variations through light diffraction and recorded it with a digital high speed camera. This set-up enabled us to study the influence of foil kinematics on vortex-wake interactions. We varied the dimensionless wavelength of the foil (l*=4-24) at a constant dimensionless flapping amplitude (A*=1.5) and geometric angle of attack amplitude (A(alpha,geo)= 15 degrees). The corresponding Reynolds number was of the order of 1000. Such values are relevant for animal swimming and flight.We found that a significant leading edge vortex (LEV) was generated by the foil at low dimensionless wavelengths (l*