In this paper, a new particle-based fluid–rigid-body interaction simulator for violent free-surface flow problems is developed. The incompressible Smoothed Particle Hydrodynamics (ISPH) method has been proven to produce a smooth and accurate pressure distribution of free-surface fluid flow with breaking and fragmentation. Computed hydrodynamic forces can be applied onto rigid bodies, which may simultaneously experience contact or impact with the surrounding wall boundaries or another rigid body. Modeled by using the discrete element method (DEM), the contact force between rigid bodies is traditionally calculated employing the penalty approach, where a spring-based repulsive force is approximated at the vicinity of contact points depending on the deepest penetration depth. However, for high-speed collision problems involving a system of many rigid bodies, the values of approximated repulsive forces may be highly overestimated, and thus, a much smaller time step and an excessive damping parameter are often required to stabilize the approximated forces. This problem is highly inefficient for the computational resources of the fluid–rigid body interaction simulation since the computational cost at each time step is mostly dominated by the incompressible fluid simulation. The capability to increase the time increment following the critical time step of the fluid solver is, therefore, strongly demanded to increase the simulation efficiency. The current paper incorporates the usage of the energy-tracking impulse (ETI) method as an alternative approach to handle contact accurately. To achieve better energy conservation and enhance stability, Stronge’s hypothesis is considered instead of the generally assumed Newton’s contact law. The current work also covers three experimental validation tests, which were conducted to assure the quality and robustness of the coupled ISPH–DEM implementation.

在本文中，针对暴力的自由表面流动问题，开发了一种新的基于粒子的流体-刚体相互作用模拟器。事实证明，不可压缩的平滑粒子流体动力学（ISPH）方法可产生自由和平滑的自由表面流体流动，并具有破裂和破碎的压力分布。可以将计算出的水动力施加到刚体上，刚体可能同时与周围的壁边界或另一个刚体接触或碰撞。传统上，通过使用离散元方法（DEM）进行建模，通常使用惩罚方法来计算刚体之间的接触力，其中，根据接触深度的最深，在接触点附近近似基于弹簧的排斥力。然而，对于涉及由许多刚体组成的系统的高速碰撞问题，近似排斥力的值可能会被高估，因此，通常需要更小的时间步长和过多的阻尼参数来稳定近似力。对于流体-刚体相互作用模拟的计算资源，此问题效率极低，因为每个时间步长的计算成本主要由不可压缩的流体模拟控制。因此，强烈要求具有在流体求解器的关键时间步长之后增加时间增量的能力，以提高仿真效率。当前论文结合了能量跟踪脉冲（ETI）方法的使用，作为精确处理接触的替代方法。为了实现更好的节能效果并增强稳定性，考虑了Stronge的假设，而不是通常假定的牛顿接触定律。当前的工作还包括三个实验验证测试，以确保ISPH-DEM耦合实施的质量和鲁棒性。