Discrete particle simulations have become the standard in science and industrial applications exploring the properties of particulate systems. Most of such simulations rely on the concept of interacting spherical particles to describe the properties of particulates, although, the correct representation of the nonspherical particle shape is crucial for a number of applications. In this work we describe the implementation of clumps, i.e. assemblies of rigidly connected spherical particles, which can approximate given nonspherical shapes, within the \textit{MercuryDPM} particle dynamics code. \textit{MercuryDPM} contact detection algorithm is particularly efficient for polydisperse particle systems, which is essential for multilevel clumps approximating complex surfaces. We employ the existing open-source \texttt{CLUMP} library to generate clump particles. We detail the pre-processing tools providing necessary initial data, as well as the necessary adjustments of the algorithms of contact detection, collision/migration and numerical time integration. The capabilities of our implementation are illustrated for a variety of examples.

翻译：离散粒子模拟已成为探索颗粒体系性质的科学与工业应用中的标准方法。这类模拟大多依赖相互作用球形粒子的概念来描述颗粒性质，然而对于许多应用而言，正确表征非球形粒子形状至关重要。本文描述了在MercuryDPM粒子动力学代码中实现团簇（即刚性连接的球形粒子集合，可近似给定非球形形状）的方法。MercuryDPM接触检测算法对多分散粒子体系特别高效，这对于近似复杂表面的多级团簇至关重要。我们利用现有的开源CLUMP库生成团簇粒子，详细介绍了提供必要初始数据的预处理工具，以及接触检测、碰撞/迁移和数值时间积分算法的必要调整。通过多种示例展示了我们实现的性能。