Two-dimensional dipolophoretic motion of a pair of ideally polarizable particles under a uniform electric field
Two-dimensional dipolophoretic motion of a pair of ideally polarizable particles under a uniform electric field
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DOI：
10.1016/j.euromechflu.2013.03.003
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发表时间：
2013-09-01
影响因子：
2.6
通讯作者：
Kang, Sangmo
中科院分区：
文献类型：
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作者：
Kang, Sangmo
在本文中，我们对一对理想可极化（导电）圆柱形颗粒的二维双电泳运动（或组合介电泳和感应电荷电泳运动）进行了数值研究，该颗粒不带净电荷，自由悬浮在由电中性方形空腔限制的粘性电解质溶液中，在施加均匀电场下。在这项研究中，我们应用了所谓的标准模型，该模型基于双电层薄到可以忽略不计并且施加的电场足够小的假设。对于模拟，我们开发了一种基于有限体积的数值方法，其中电场的数值求解采用平滑轮廓方法，流场的数值求解采用基于直接力的浸入边界方法。结果表明，由于极强的感应电荷电泳效应，完整的介电泳运动与纯介电泳运动显着不同。对于纯介电泳，两个粒子旋转，同时根据其配置相互排斥或吸引，最后与场方向对齐。另一方面，对于完全介电电泳，两个粒子也会根据其构型进行吸引或排斥运动，但其方式与纯介电电泳的情况有很大不同：被空腔限制的两个粒子中的每一个都围绕某个点描绘螺旋轨迹，它们之间没有任何接触，并渐近地停止以在该点保持静止。 (C) 2013 Elsevier Masson SAS。版权所有。
In this paper, we have numerically studied two-dimensional dipolophoretic motion (or combined dielectrophoretic and induced-charge electrophoretic motion) of a pair of ideally polarizable (conducting) cylindrical particles carrying no net charge suspended freely in a viscous electrolyte solution confined by an electrically-neutral square cavity under an applied uniform electric field. To the study, we apply the so-called standard model based on the assumptions that the electric double layer is negligibly thin and the applied electric field is enough small. For the simulations, we develop a finite-volume based numerical approach, where a smoothed profile method is adopted for the numerical solution of the electric field and a direct-forcing based immersed-boundary method is for that of the flow field. Results show that the full dipolophoretic motion differs significantly from the pure dielectrophoretic motion due to an overwhelmingly strong induced-charge electrophoretic effect. For the pure dielectrophoresis, two particles revolve while repelling or attracting each other depending on their configuration and finally get aligned in a line with the field direction. For the full dipolophoresis, on the other hand, two particles also take attractive or repulsive motion according to their configuration, but in a fashion greatly different from the case of pure dielectrophoresis: each of two particles confined by a cavity traces a spiral trajectory around a certain point without any contact between them and asymptotically stops to remain stationary at that point. (C) 2013 Elsevier Masson SAS. All rights reserved.