An integrated boundary approach for colloidal suspensions simulated using smoothed dissipative particle dynamics
An integrated boundary approach for colloidal suspensions simulated using smoothed dissipative particle dynamics
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DOI：
10.1016/j.compfluid.2018.11.025
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发表时间：
2019-01
影响因子：
2.8
通讯作者：
N. Petsev;L. Leal;M. Shell
中科院分区：
文献类型：
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作者：
N. Petsev;L. Leal;M. Shell
在基于粒子的连续体求解器中，例如平滑粒子流体动力学 (SPH) 和平滑耗散粒子动力学 (SDPD)，最重大的挑战之一是对壁和胶体粒子等固体边界的处理，它们的存在会导致积分近似值的截断，从而导致数值解中的错误。在这项工作中，我们描述了一个用于模拟由刚性球形颗粒组成的胶体悬浮液的集成边界框架。对与胶体贡献相对应的积分进行分析评估，给出相对于传统边界粒子技术的简单且计算成本低的方法。我们为介尺度模拟制定了这种自上而下方法的热力学一致版本，其中流体由于热波动而与悬浮颗粒交换动量，从而为任意雷诺数和佩克莱特数下的胶体动力学建模提供了一个框架。由此产生的演化方程针对恒温流体中的单个胶体颗粒进行了验证。相对于传统的边界粒子策略，这种简单的方法需要~ N c (ρ/m) R c 2 更少的对力计算，其中 N c 是系统中胶体的数量，R c 是胶体半径，ρ 是胶体质量密度，m 是 SDPD 粒子的质量。此外，集成边界的使用消除了对刚体约束动力学的需求，为胶体悬浮液的大规模模拟提供了优雅且有效的基础，该模拟是通用的并且不对流动做出任何物理假设。
In particle-based continuum solvers such as smoothed particle hydrodynamics (SPH) and smoothed dissipative particle dynamics (SDPD), one of the most significant challenges is the treatment of solid boundaries like walls and colloidal particles, whose presence leads to a truncation of the integral approximation, and hence, error in the numerical solution. In this work, we describe an integrated boundary framework for modeling colloidal suspensions composed of rigid spherical particles. The integral corresponding to the colloid's contribution is analytically evaluated, giving a simple and computationally inexpensive approach relative to conventional boundary particle techniques. We formulate a thermodynamically-consistent version of this top-down method for mesoscale simulations, in which the fluid exchanges momentum with the suspended particles due to thermal fluctuations, giving a framework for modeling the dynamics of colloids at arbitrary Reynolds and Péclet numbers. The resulting evolution equations are validated for a single colloidal particle in a fluid at constant temperature. This simple approach requires∼ N c (ρ/m) R c 2 fewer pair force calculations relative to traditional boundary particle strategies, where N c is the number of colloids in the system, R c is the colloid radius, ρ is the colloid mass density, and m is the mass of the SDPD particles. In addition, the use of integrated boundaries removes the need for rigidbody constraint dynamics, giving an elegant and efficient basis for large-scale simulations of colloidal suspensions that is general and does not make any physical assumptions about the flow.