Propulsion of a Two-Sphere Swimmer.
Propulsion of a Two-Sphere Swimmer.
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DOI：
10.1103/physrevlett.115.248102
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发表时间：
2015-01
影响因子：
8.6
通讯作者：
D. Klotsa;K. A. Baldwin;R. Hill;R. Bowley;M. Swift
中科院分区：
文献类型：
--
作者：
D. Klotsa;K. A. Baldwin;R. Hill;R. Bowley;M. Swift
我们描述的实验和模拟演示的推进力的中性浮力游泳者，由一对球体连接的弹簧，沉浸在振动的流体。流体的振动引起球体的相对运动，对于足够大的振幅，这可以导致两个球体的质心的运动。我们发现，从实验和模拟获得的游泳速度同意和崩溃到一个单一的曲线上，如果绘制作为流雷诺数的函数，这表明，推进流有关。似乎有一个临界值的流动雷诺数游泳发生。随着雷诺数的增加，我们观察到流动的变化，从两个独立的振荡球体产生的集体流动模式周围的游泳者作为一个整体。游泳的机制可以追溯到加强游泳者身后的流体射流。
We describe experiments and simulations demonstrating the propulsion of a neutrally buoyant swimmer that consists of a pair of spheres attached by a spring, immersed in a vibrating fluid. The vibration of the fluid induces relative motion of the spheres which, for sufficiently large amplitudes, can lead to motion of the center of mass of the two spheres. We find that the swimming speed obtained from both experiment and simulation agree and collapse onto a single curve if plotted as a function of the streaming Reynolds number, suggesting that the propulsion is related to streaming flows. There appears to be a critical onset value of the streaming Reynolds number for swimming to occur. We observe a change in the streaming flows as the Reynolds number increases, from that generated by two independent oscillating spheres to a collective flow pattern around the swimmer as a whole. The mechanism for swimming is traced to a strengthening of a jet of fluid in the wake of the swimmer.