The multiparticle collision dynamics (MPCD) simulation method is an attractive technique for studying the effects of hydrodynamic interactions in colloidal suspensions because of its flexibility, computational efficiency, and ease of implementation. Here, we analyze an extension of the basic MPCD method in which colloidal particles are discretized with a surface mesh of sensor nodes/particles that interact with solvent particles (MPCD + Discrete Particle or MPCD + DP). We use several situations that have been described analytically to probe the impact of colloidal particle mesh resolution on the ability of the MPCD + DP method to resolve short-ranged hydrodynamic interactions, which are important in crowded suspensions and especially in self-assembling systems that create high volume fraction phases. Specifically, we consider (A) hard-sphere diffusion near a wall, (B) two-particle diffusion, (C) hard-sphere diffusion in crowded suspensions, and (D) the dynamics of aggregation in an attractive colloidal suspension. We show that in each case, the density of sensor nodes plays a significant role in the accuracy of the simulation and that a surprisingly high number of surface nodes are needed to fully capture hydrodynamic interactions.

中文翻译：

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胶体悬浮液中流体动力学相互作用的多粒子碰撞动力学模拟：离散粒子方法在短距离内的表现如何？

多粒子碰撞动力学 (MPCD) 模拟方法由于其灵活性、计算效率和易于实施而成为研究胶体悬浮液中流体动力相互作用影响的一种有吸引力的技术。在这里，我们分析了基本 MPCD 方法的扩展，其中胶体颗粒通过与溶剂颗粒相互作用的传感器节点/颗粒的表面网格进行离散化（MPCD + 离散颗粒或 MPCD + DP）。我们使用已分析描述的几种情况来探讨胶体颗粒网格分辨率对 MPCD + DP 方法解决短程流体动力学相互作用的能力的影响，这在拥挤的悬浮液中非常重要，尤其是在产生高体积分数相。具体来说，我们考虑（A）靠近壁的硬球扩散，（B）双粒子扩散，（C）拥挤悬浮液中的硬球扩散，以及（D）有吸引力的胶体悬浮液中的聚集动力学。我们表明，在每种情况下，传感器节点的密度对模拟的准确性都起着重要作用，并且需要数量惊人的表面节点才能完全捕获流体动力相互作用。