Active turbulence in a gas of self-assembled spinners.
Active turbulence in a gas of self-assembled spinners.
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DOI：
10.1073/pnas.1710188114
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发表时间：
2017-12-05
影响因子：
11.1
通讯作者：
Snezhko A
中科院分区：
文献类型：
--
作者：
Kokot G;Das S;Winkler RG;Gompper G;Aranson IS;Snezhko A
湍流运动在自然界中广泛存在，并且可以在不同的长度和时间尺度上观察到，范围从高雷诺数流体力学到活性流体，如细菌悬浮液和细胞骨架提取物。它被认为是理论物理学中尚未解决的挑战之一。在这里，我们探索了液体界面上的非平衡磁性胶体粒子，它们表现出复杂的集体行为，导致活跃旋转相的出现。自组装旋流器（主动旋流而非自推进）诱导强烈的涡旋，展示了二维流体动力学湍流的特性。我们的研究结果提供了对活性旋转液体行为的深入了解，以及控制活性胶体材料集体动力学和运输的方法。受外部周期性强迫作用的胶体粒子表现出复杂的集体行为和自组装模式。磁性微粒的分散被限制在气液界面，并在均匀的单轴交变磁场的激励下，呈现出自组装的自旋器在任何方向旋转的动态阵列。在这里，我们报告了自组装旋转体气体中主动湍流和输运的实验和模拟研究。我们表明，自组装粒子链的时钟/逆时针旋转自发对称性破坏的结果是自旋子，在界面上产生强烈的涡旋流。由于自生平流，旋旋体系综表现出混沌动力学。同手性旋旋体（顺时针或逆时针）表现出聚集并形成动态簇的趋势。自发的界面电流促进主动扩散，这种扩散可以通过外部激励场的参数来调节。此外，旋转器在界面处的不稳定运动产生了令人联想到二维湍流的混沌流体流动。我们的工作提供了对活性旋转材料集体输运的基本方面的见解，并在微观尺度上产生了粒子操纵的规则。
Turbulent fluid motion is widespread in nature and is observed across diverse length and time scales, ranging from high-Reynolds number hydrodynamics to active fluids, such as bacterial suspensions and cytoskeletal extracts. It is recognized as one of the unsolved challenges in theoretical physics. Here, we explore out-of-equilibrium magnetic colloidal particles at liquid interfaces that exhibit complex collective behavior, resulting in emergence of an active spinner phase. Self-assembled spinners (active spinning without self-propulsion) induce vigorous vortical flows, demonstrating the properties of a 2D hydrodynamic turbulence. Our findings provide insight into the behavior of active spinner liquids and ways to control the collective dynamics and transport in active colloidal materials. Colloidal particles subject to an external periodic forcing exhibit complex collective behavior and self-assembled patterns. A dispersion of magnetic microparticles confined at the air–liquid interface and energized by a uniform uniaxial alternating magnetic field exhibits dynamic arrays of self-assembled spinners rotating in either direction. Here, we report on experimental and simulation studies of active turbulence and transport in a gas of self-assembled spinners. We show that the spinners, emerging as a result of spontaneous symmetry breaking of clock/counterclockwise rotation of self-assembled particle chains, generate vigorous vortical flows at the interface. An ensemble of spinners exhibits chaotic dynamics due to self-generated advection flows. The same-chirality spinners (clockwise or counterclockwise) show a tendency to aggregate and form dynamic clusters. Emergent self-induced interface currents promote active diffusion that could be tuned by the parameters of the external excitation field. Furthermore, the erratic motion of spinners at the interface generates chaotic fluid flow reminiscent of 2D turbulence. Our work provides insight into fundamental aspects of collective transport in active spinner materials and yields rules for particle manipulation at the microscale.
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影响因子：
13.6
作者：
Kaiser A;Snezhko A;Aranson IS
通讯作者：
Aranson IS
影响因子：
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作者：
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影响因子：
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作者：
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影响因子：
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作者：
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影响因子：
8.6
作者：
Dombrowski, C;Cisneros, L;Kessler, JO
通讯作者：
Kessler, JO