Characterization of azimuthal and radial velocity fields induced by rotors in flows with a low Reynolds number.
Characterization of azimuthal and radial velocity fields induced by rotors in flows with a low Reynolds number.
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低雷诺数流中转子引起的方位角和径向速度场的表征
DOI：
10.1103/physreve.93.023108
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Evgeny L. Gurevich
中科院分区：
文献类型：
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作者：
Jannis Köhler;Jan Friedrich;Andreas Ostendorf;Evgeny L. Gurevich
本文从理论和实验两方面研究了绕中心非轴对称旋转的棒状微转子的流场。提出了一个简单的理论模型，使用叠加的两个rotlets作为一个基本的解决方案的斯托克斯方程。该模型的预测相比，由转子组成的熔融微观球引起的方位角和径向微流体速度场分量的测量。转子是磁驱动的，流体流量的测量与光镊固定的探针粒子的帮助下。我们发现相当大的偏差，仅仅由一个单一的旋转球引起的方位角流动模式，因为它已被报道的迪Leonardoet等人。[Phys. Rev. Lett. 96，134502（2006）PRLTA00031 -900710.1103/PhysRevLett.96.134502]。值得注意的是，观察到的径向速度分量的存在下，表现出自己的探针粒子的振荡与转子频率的两倍。这些发现开辟了一种方法来讨论可能的径向传输微流体装置。
We theoretically and experimentally investigate the flow field that emerges from a rodlike microrotor rotating about its center in a nonaxisymmetric manner. A simple theoretical model is proposed that uses a superposition of two rotlets as a fundamental solution to the Stokes equation. The predictions of this model are compared to measurements of the azimuthal and radial microfluidic velocity field components that are induced by a rotor composed of fused microscopic spheres. The rotor is driven magnetically and the fluid flow is measured with the help of a probe particle fixed by an optical tweezer. We find considerable deviations of the mere azimuthal flow pattern induced by a single rotating sphere as it has been reported by Di Leonardoet al.[Phys. Rev. Lett. 96, 134502 (2006)PRLTAO0031-900710.1103/PhysRevLett.96.134502]. Notably, the presence of a radial velocity component that manifests itself by an oscillation of the probe particle with twice the rotor frequency is observed. These findings open up a way to discuss possible radial transport in microfluidic devices.