Accelerated Stokesian dynamics: Brownian motion
Accelerated Stokesian dynamics: Brownian motion
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DOI：
10.1063/1.1571819
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发表时间：
2003-06-08
影响因子：
4.4
通讯作者：
Brady, JF
中科院分区：
文献类型：
--
作者：
Banchio, AJ;Brady, JF
提出了一种新的布朗悬架Stokesian动力学（SD）算法。该实现基于最近开发的非布朗粒子加速斯托克动力学（ASD）模拟方法[Sierou和Brady， J.流体力学，448,115(2001)]。与ASD中一样，采用快速傅里叶变换计算多体远程水动力相互作用，并迭代反转阻力矩阵，以保持计算成本为O（N log N）。采用一种快速计算作用在粒子上的布朗力的方法，将它们分为近场和远场贡献，以避免对全电阻矩阵的平方根进行O（N-3）计算。对于近场部分，将力表示为成对贡献的总和，将成本降低到O(N)；对于远场部分，迁移率矩阵平方根逆的切比雪夫多项式近似计算成本为0 （N-1.25 log N）。因此，该方法的总体标度大致为0 (N-1.25 log N)，使得模拟大型系统成为可能，这对于研究胶体分散体的长期动力学性质和/或多分散性效应是必要的。本文将该方法应用于浓胶悬浮液的流变学研究，并与常规SD进行了比较。提出了一种更快的近似方法，并对其精度进行了讨论。(C) 2003年美国物理研究所。
A new Stokesian dynamics (SD) algorithm for Brownian suspensions is presented. The implementation is based on the recently developed accelerated Stokesian dynamics (ASD) simulation method [Sierou and Brady, J. Fluid Mech. 448, 115 (2001)] for non-Brownian particles. As in ASD, the many-body long-range hydrodynamic interactions are computed using fast Fourier transforms, and the resistance matrix is inverted iteratively, in order to keep the computational cost O(N log N). A fast method for computing the Brownian forces acting on the particles is applied by splitting them into near- and far-field contributions to avoid the O(N-3) computation of the square root of the full resistance matrix. For the near- field part, representing the forces as a sum of pairwise contributions reduces the cost to O(N); and for the far-field part, a Chebyshev polynomial approximation for the inverse of the square root of the mobility matrix results in an O(N-1.25 log N) computational cost. The overall scaling of the method is thus roughly of O(N-1.25 log N) and makes possible the simulation of large systems, which are necessary for studying long-time dynamical properties and/or polydispersity effects in colloidal dispersions. In this work the method is applied to study the rheology of concentrated colloidal suspensions, and results are compared with conventional SD. Also, a faster approximate method is presented and its accuracy discussed. (C) 2003 American Institute of Physics.