Using Curved Fluid Boundaries to Confine Active Nematic Flows
Using Curved Fluid Boundaries to Confine Active Nematic Flows
复制标题
DOI：
10.3389/fphy.2022.880941
复制
发表时间：
2022-04-27
影响因子：
3.1
通讯作者：
Hirst, Linda S.
中科院分区：
文献类型：
--
作者：
Khaladj, Dimitrius A.;Hirst, Linda S.
由分子马达驱动的主动驱动、束状微管网络已经成为研究能量驱动缺陷动力学的有用框架，但实现对缺陷运动的控制仍然是一个具有挑战性的问题。在本文中，我们提出了一种通过润湿在圆形柱子上弯曲一层油层来限制活动向列流体的方法。在这种几何形状中，被淹没的柱子撞击到油水界面上，形成了一个两层连续的活性层，材料被限制在上面，并包围着柱子。柱子上方的活性流动受圆形几何形状的影响，表现出类似于观察到的受硬边界限制的活性物质的动力学，例如在圆形井内。活性物质下面的薄油层在柱子上方的区域比在其边界之外的区域更薄，因此产生了更高的有效摩擦区。在柱状区内，相对于柱状区外，有效长度尺度和速度减小，而缺陷密度增加。这种限制主动流的新方法为控制和组织拓扑缺陷以及研究它们在主动系统中的行为提供了更多的机会。
Actively driven, bundled microtubule networks, powered by molecular motors have become a useful framework in which to study the dynamics of energy-driven defects, but achieving control of defect motions is still a challenging problem. In this paper, we present a method to confine active nematic fluid using wetting to curve a layer of oil over circular pillars. This geometry, in which submersed pillars impinge on an oil-water interface, creates a two-tier continuous active layer in which the material is confined above, and surrounds the pillars. Active flows above the pillars are influenced by the circular geometry and exhibit dynamics similar to those observed for active material confined by hard boundaries, e.g., inside circular wells. The thin oil layer beneath the active material is even thinner in the region above the pillars than outside their boundary, consequently producing an area of higher effective friction. Within the pillar region, active length scales and velocities are decreased, while defect densities increase relative to outside the pillar boundary. This new way to confine active flows opens further opportunities to control and organize topological defects and study their behavior in active systems.