Flow over a traveling wavy foil with a passively flapping flat plate.
Flow over a traveling wavy foil with a passively flapping flat plate.
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DOI：
10.1103/physreve.85.056316
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发表时间：
2012-05
期刊：
影响因子：
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通讯作者：
Nansheng Liu;Yan Peng;Youwen Liang;Xi-yun Lu
中科院分区：
文献类型：
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作者：
Nansheng Liu;Yan Peng;Youwen Liang;Xi-yun Lu
采用多块格子Boltzmann方程和浸入边界方法研究了带有被动拍动平板的行波翼型绕流。翼片在横向上经历规定的波动，刚性平板具有由流体结构相互作用确定的被动运动。利用该简化模型研究了鱼类尾鳍及其柔性对游泳动物运动的影响。尾鳍的柔韧性是由一个扭转弹簧模拟的，该扭转弹簧作用在波浪形箔片和平板的接合处的枢轴上。研究表明，被动振动平板贡献了一半的推进力。以无量纲固有频率F表示的柔度对整个物体的运动和推进力的产生起着非常重要的作用。当板太柔性时，观察到拖曳力。随着平板变得更加刚性，当波动被限制在波状翼片的最后部分时产生的推进力变得更大。稳定运动发生在F = 5时。这些结果与自然界中一些游泳动物的观察结果一致。
Flow over a traveling wavy foil with a passively flapping flat plate has been investigated using a multiblock lattice Boltzmann equation and the immersed boundary method. The foil undergoes prescribed undulations in the lateral direction and the rigid flat plate has passive motion determined by the fluid structure interaction. This simplified model is used to study the effect of the fish caudal fin and its flexibility on the locomotion of swimming animals. The flexibility of the caudal fin is modeled by a torsion spring acting about the pivot at the conjuncture of the wavy foil and the flat plate. The study reveals that the passively oscillating flat plate contributes half of the propulsive force. The flexibility, represented by the nondimensional natural frequency F, plays a very important role in the movement and propulsive force generation of the whole body. When the plate is too flexible, the drag force is observed. As the flat plate becomes more rigid, the propulsive force that is generated when the undulation is confined to last part of the wavy foil becomes larger. The steady movement occurs at F=5. These results are consistent with the observations of some swimming animals in nature.