Hu Shiyuan, Zhang Jun, Shelley Michael J
Applied Mathematics Lab, Courant Institute of Mathematical Sciences, New York University, New York, NY 10012, USA.
Department of Physics, New York University, New York, NY 10003, USA.
Soft Matter. 2022 May 11;18(18):3605-3612. doi: 10.1039/d2sm00292b.
A single flexible filament can be actuated to escape from the scallop theorem and generate net propulsion at low Reynolds number. In this work, we study the dynamics of a simple boundary-driven multi-filament swimmer, a two-arm clamshell actuated at the hinged point, using a nonlocal slender body approximation with hydrodynamic interactions. We first consider an elastic clamshell consisted of flexible filaments with intrinsic curvature, and then build segmental models consisted of rigid segments connected by different mechanical joints with different forms of response torques. The simplicity of the system allows us to fully explore the effect of various parameters on the swimming performance. Optimal included angles and elastoviscous numbers are identified. The segmental models capture the characteristic dynamics of the elastic clamshell. We further demonstrate how the swimming performance can be significantly enhanced by the asymmetric beating patterns induced by biased torques.
一根柔性细丝可以被驱动以摆脱扇贝定理，并在低雷诺数下产生净推进力。在这项工作中，我们使用具有流体动力相互作用的非局部细长体近似方法，研究了一个简单的边界驱动多细丝游泳者（即在铰接点处驱动的双臂蛤壳）的动力学。我们首先考虑由具有固有曲率的柔性细丝组成的弹性蛤壳，然后构建由通过具有不同形式响应扭矩的不同机械关节连接的刚性段组成的分段模型。该系统的简单性使我们能够充分探索各种参数对游泳性能的影响。确定了最佳夹角和弹性粘性数。分段模型捕捉了弹性蛤壳的特征动力学。我们进一步证明了由偏置扭矩引起的不对称拍打模式如何能够显著提高游泳性能。
