Abstract We have developed a highly efficient and portable fluid–structure interaction (FSI) simulation package, so-called OpenFSI. Within this package, the structure dynamics is accounted by a lattice model (LM) implemented in the framework of Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), demonstrating the same accuracy as finite element analysis. The fluid flow is resolved by Palabos, which adopts the Lattice Boltzmann method (LBM) to efficiently solve the Boltzmann equation that can recover the Navier–Stokes equation in mesoscale. Additionally, the immersed boundary method (IBM) is employed to couple LM and LBM together, therefore endowing the flexibility to choose alternative solid and fluid solvers. The whole simulation is fulfilled within the framework of Palabos, and the LAMMPS framework is called in Palabos as an external library and coupled through IBM. To demonstrate the capability and accuracy of the proposed package, the validations for the LM are first performed by conducting the deflections of two-dimensional (2D) and three-dimensional (3D) beams in LAMMPS, and comparing the results with those in finite element analysis. Followed are the classical benchmarks of flow passing 2D flexible beam behind a cylinder and 3D flow passing a fixed cylinder. In the results, the free-falling of spheres and flapping of a deformable plate in cross-flow are investigated. Furthermore, the possibility to study complex FSI phenomena is demonstrated by the cases of spheres passing a dam and swimming of microswimmers. Lastly, the efficiency of this simulation package is explored by examining an extremely large system with thousands of red blood cells in blood flow. The OpenFSI package is found to have excellent linear scalability up to 8192 processors, due to the particle-based LM and LBM for structure and fluid flow respectively, as well as advanced cyberinfrastructure of LAMMPS package. Therefore, OpenFSI presents an alternative option to efficiently solve large scale FSI problems, hence to facilitate the unveiling of underlying physical mechanisms.

中文翻译：

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OpenFSI：一种基于浸入边界法的高效便携流固耦合仿真包

摘要 我们开发了一种高效且便携的流固耦合 (FSI) 仿真包，即所谓的 OpenFSI。在这个包中，结构动力学由在大规模原子/分子大规模并行模拟器 (LAMMPS) 框架中实现的晶格模型 (LM) 计算，证明与有限元分析相同的精度。流体流动由Palabos求解，它采用格子玻尔兹曼方法（LBM）有效求解玻尔兹曼方程，可以在中尺度恢复纳维-斯托克斯方程。此外，浸入边界法 (IBM) 用于将 LM 和 LBM 耦合在一起，因此可以灵活地选择替代的固体和流体求解器。整个模拟在 Palabos 框架内完成，LAMMPS 框架在 Palabos 中被称为外部库，并通过 IBM 耦合。为了证明所提出的程序包的能力和准确性，首先通过在 LAMMPS 中进行二维 (2D) 和三维 (3D) 梁的偏转，并将结果与​​有限元中的结果进行比较来对 LM 进行验证分析。以下是流经圆柱体后面的 2D 柔性梁和流经固定圆柱体的 3D 流的经典基准。在结果中，研究了球体的自由落体和横流中可变形板的拍打。此外，球体通过大坝和微型游泳者游泳的案例证明了研究复杂 FSI 现象的可能性。最后，通过检查血流中有数千个红细胞的超大型系统来探索该模拟包的效率。由于分别用于结构和流体流动的基于粒子的 LM 和 LBM，以及 LAMMPS 包的先进网络基础设施，OpenFSI 包被发现具有高达 8192 个处理器的出色线性可扩展性。因此，OpenFSI 提供了一种有效解决大规模 FSI 问题的替代选择，从而有助于揭示底层物理机制。