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arXiv 1607.04572cond-mat.softphysics.flu-dyn
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格子Boltzmann电动力学中带电粒子的运动

Moving Charged Particles in Lattice Boltzmann-Based Electrokinetics

Michael Kuron, Georg Rempfer, Florian Schornbaum, Martin Bauer, Christian Godenschwager, Christian Holm, Joost de Graaf

摘要:

离子溶质和带电粒子在电场的影响下的运动以及随后的底层溶剂的流体动力学流动在水性胶体悬浮液中是普遍存在的。这种系统的物理学是由一组耦合的微分方程和边界条件描述的,统称为电动方程。Capuani等人[J.Chem.Phys.121,973(2004)]介绍了一种用于求解该方程组的基于格子的方法,该方法建立在用于模拟流体动力学流动的格子Boltzmann算法的基础上,并利用了计算局部性。然而,到目前为止,如何将移动边界条件的Capuani计划的描述一直缺乏。模拟多个任意运动的胶体时需要移动边界条件。在本文中,我们详细介绍了如何引入这样的粒子耦合方案,基于模拟的纯LB求解器的移动边界方法。在我们的方法中的关键成分是溶质物种的质量和电荷守恒和溶质通量的部分体积平滑,以尽量减少离散化文物。我们证明了我们的算法的有效性,通过模拟带电球体在外场中的电泳,对于一个单一的球,我们比较等效的电渗(共同移动)的问题。我们的方法的效率和易于实施应证明有利于未来的动态模拟在广泛的复杂的纳米和胶体系统,以前无法访问基于晶格的连续体算法。

英文摘要:

The motion of ionic solutes and charged particles under the influence of an electric field and the ensuing hydrodynamic flow of the underlying solvent is ubiquitous in aqueous colloidal suspensions. The physics of such systems is described by a coupled set of differential equations, along with boundary conditions, collectively referred to as the electrokinetic equations. Capuani et al. [J. Chem. Phys. 121, 973 (2004)] introduced a lattice-based method for solving this system of equations, which builds upon the lattice Boltzmann algorithm for the simulation of hydrodynamic flow and exploits computational locality. However, thus far, a description of how to incorporate moving boundary conditions into the Capuani scheme has been lacking. Moving boundary conditions are needed to simulate multiple arbitrarily-moving colloids. In this paper, we detail how to introduce such a particle coupling scheme, based on an analogue to the moving boundary method for the pure LB solver. The key ingredients in our method are mass and charge conservation for the solute species and a partial-volume smoothing of the solute fluxes to minimize discretization artifacts. We demonstrate our algorithm's effectiveness by simulating the electrophoresis of charged spheres in an external field; for a single sphere we compare to the equivalent electro-osmotic (co-moving) problem. Our method's efficiency and ease of implementation should prove beneficial to future simulations of the dynamics in a wide range of complex nanoscopic and colloidal systems that was previously inaccessible to lattice-based continuum algorithms.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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