A study of self-propelled elastic cylindrical micro-swimmers using modeling and computation
A study of self-propelled elastic cylindrical micro-swimmers using modeling and computation
复制标题
自驱动弹性圆柱微型游泳器的建模与计算研究
DOI：
10.1016/j.jcp.2016.02.071
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
T. Pan
中科院分区：
文献类型：
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作者：
Lingling Shi;S. Čanić;A. Quaini;T. Pan
研究了微型游泳者在三维蠕动流中的推进特性。游泳者被假定是由弹性圆柱形空心管。游泳是由管的弹性膜壁的收缩产生的，该收缩以“阶跃函数”的形式产生行波，该行波从右向左穿过游泳者，从左向右推动游泳者。这个问题的动机是医疗应用，如药物输送。几个无量纲的设计参数对游泳者的速度的影响进行了研究，包括游泳者的长宽比，和相对于游泳者半径的行波的振幅。将基于有限元法的浸入边界法与弹性弹簧网络模型相结合，成功地模拟了弹性圆柱管与三维粘性不可压缩流体之间的双向流固耦合问题。为了更深入地了解各种参数对游泳者速度的影响，推导并验证了简化的一维流固耦合模型。结果发现，快速游泳者是那些具有大的管的纵横比，并与行波的振幅，这是大约50%的参考游泳者半径。结果表明，我们的“最佳游泳者”的速度约为每秒1.5个游泳者长度，这是目前制造的所有微型游泳者在低雷诺数流（Re= 10− 6）中游泳的最高速度，见[11]。
We study propulsion of micro-swimmers in 3D creeping flow. The swimmers are assumed to be made of elastic cylindrical hollow tubes. The swimming is generated by the contractions of the tube's elastic membrane walls producing a traveling wave in the form of a “step-function” traversing the swimmer from right to left, propelling the swimmer from left to right. The problem is motivated by medical applications such as drug delivery. The influence of several non-dimensional design parameters on the velocity of the swimmer is investigated, including the swimmer aspect ratio, and the amplitude of the traveling wave relative to the swimmer radius. An immersed boundary method based on a finite element method approach is successfully combined with an elastic spring network model to simulate the two-way fluid–structure interaction coupling between the elastic cylindrical tube and the flow of a 3D viscous, incompressible fluid. To gain a deeper insight into the influence of various parameters on the swimmer speed, a reduced 1D fluid–structure interaction model was derived and validated. It was found that fast swimmers are those with large tube aspect ratios, and with the amplitude of the traveling wave which is roughly 50% of the reference swimmer radius. It was shown that the speed of our “optimal swimmer” is around 1.5 swimmer lengths per second, which is at the top of the class of all currently manufactured micro-swimmers swimming in low Reynolds number flows (Re= 10− 6), reported in [11].