标题： 多分辨率SPH框架：多相流体-结构相互作用的应用 显示英文标题

标题： A multi-resolution SPH framework: Application to multi-phase fluid-structure interactions

摘要： 在之前的工作中，张等人提出了一个多层次平滑粒子流体动力学（SPH）方法，用于流体-结构相互作用（FSI），在实现优化的计算效率的同时保持良好的数值鲁棒性和准确性。在本文中，这个不同子系统应用不同空间-时间离散化的多层次SPH框架被扩展到涉及大密度比并与其相互作用的多相流中。为此，通过利用不同的密度再初始化策略，而不是分别对轻相和重相应用不同的公式来实现质量守恒，引入了一个简单且高效的多相模型，以实现使用相同的人工声速的目标。为了消除不自然的空隙和不现实的相分离，同时减少数值耗散，运输速度公式通过应用时间局部流动状态依赖的背景压力进行了重写。为了处理三相点中单分辨率和多分辨率情况下的FSI耦合，采用了基于单侧Riemann的固体边界条件。研究了一组涉及高密度比和复杂界面的多相流以及多相FSI的例子，以展示该方法的效率、准确性和鲁棒性。此处提供的验证以及张等人原始论文中关于单相FSI的研究，使该多分辨率SPH框架在多物理场应用的计算效率方面处于良好状态。 显示英文摘要

摘要： In the previous work, Zhang et al. proposed a multi-resolution smoothed particle hydrodynamics (SPH) method for fluid-structure interactions (FSI) with achieving an optimized computational efficiency meanwhile maintaining good numerical robustness and accuracy. In the present paper, this multi-resolution SPH framework where different spatial-temporal discretizations are applied for different sub-systems is extended to multi-phase flows involving large density ratio and interacting with rigid or flexible structure. To this end, a simple and efficient multi-phase model is introduced by exploiting different density reinitialization strategies other than applying different formulations to implement mass conservation to the light and heavy phases, respectively, to realize the target of using same artificial speed of sound for the both. To eliminate the unnatural voids and unrealistic phase separation meanwhile decrease the numerical dissipation, the transport velocity formulation are rewritten by applying temporal local flow state dependent background pressure. To handle the FSI coupling in both single- and multi-resolution scenarios in the triple point, the one-sided Riemann-based solid boundary condition is adopted. A set of examples involving multi-phase flows with high density ratio and complex interface and multi-phase FSI are studied to demonstrate the efficiency, accuracy and robustness of the present method. The validations presented herein and those reported in the original paper of Zhang et al. where single-phase FSI is studied put the present multi-resolution SPH framework in good stead in terms of computational efficiency for multi-physics applications.