Organizing bacterial vortex lattices by periodic obstacle arrays
Organizing bacterial vortex lattices by periodic obstacle arrays
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DOI：
10.1038/s42005-020-0337-z
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发表时间：
2020-05-07
影响因子：
5.5
通讯作者：
Aranson, Igor S.
中科院分区：
文献类型：
--
作者：
Reinken, Henning;Nishiguchi, Daiki;Aranson, Igor S.
最近的实验表明，在活动流体中出现的复杂时空涡结构容易受到弱几何约束的影响。这一观察结果提出了一个基本问题，即边界效应如何从看似湍流的运动中稳定一个高度有序的模式。在这里，我们通过结合连续介质理论和细菌悬浮液的实验，展示了人工障碍物如何引导流动轮廓和重组拓扑缺陷，从而能够设计具有可调特性的细菌漩涡晶格。为此，通过适当的边界条件对连续统模型进行了扩展。除了正方形和六边形晶格的稳定性之外，我们还提供了一个引人注目的手性反铁磁晶格的净旋转流的例子，这是通过将障碍物排列在一个类似kagome的阵列中引起的。最近的实验表明，弱几何约束可以在湍流细菌悬浮液中组织拓扑缺陷。本文采用连续介质模型研究了紧急涡型的对称性和稳定性与约束柱阵几何结构之间的关系。
Recent experiments have shown that the complex spatio-temporal vortex structures emerging in active fluids are susceptible to weak geometrical constraints. This observation poses the fundamental question of how boundary effects stabilize a highly ordered pattern from seemingly turbulent motion. Here we show, by a combination of continuum theory and experiments on a bacterial suspension, how artificial obstacles guide the flow profile and reorganize topological defects, which enables the design of bacterial vortex lattices with tunable properties. To this end, the continuum model is extended by appropriate boundary conditions. Beyond the stabilization of square and hexagonal lattices, we also provide a striking example of a chiral, antiferromagnetic lattice exhibiting a net rotational flow, which is induced by arranging the obstacles in a Kagome-like array. Recent experiments showed that weak geometrical constraints can organize topological defects in turbulent bacterial suspensions. Here, the authors use a continuum model to study the connection between symmetry and stability of emergent vortex patterns and the geometry of constraining pillar arrays.