A parallel solver framework for fully implicit monolithic fluid-structure interaction  

一种全隐式整体流固耦合的并行计算框架

作　　者：Yujie Sun Qingshuang Lu Ju Liu 孙钰杰;卢清霜;刘巨

机构地区：[1]Department of Mechanics and Aerospace Engineering,Southern University of Science and Technology,Shenzhen 518055,China [2]Guangdong-Hong Kong-Macao Joint Laboratory for Data-Driven Fluid Mechanics and Engineering Applications,Southern University of Science and Technology,Shenzhen 518055,China

出　　处：《Acta Mechanica Sinica》2025年第2期88-115,共28页力学学报(英文版)

基　　金：This work was supported by the National Natural Science Foundation of China(Grant No.12172160);Shenzhen Science and Technology Program(Grant No.JCYJ20220818100600002);South-ern University of Science and Technology(Grant No.Y01326127);the Department of Science and Technology of Guangdong Province(Grant Nos.2020B1212030001 and 2021QN020642).

摘　　要：We propose a suite of strategies for the parallel solution of fully implicit monolithic fluid-structure interaction(FSI).The solver is based on a modeling approach that uses the velocity and pressure as the primitive variables,which offers a bridge between computational fluid dynamics(CFD)and computational structural dynamics.The spatiotemporal discretization leverages the variational multiscale formulation and the generalized-αmethod as a means of providing a robust discrete scheme.In particular,the time integration scheme does not suffer from the overshoot phenomenon and optimally dissipates high-frequency spurious modes in both subproblems of FSI.Based on the chosen fully implicit scheme,we systematically develop a combined suite of nonlinear and linear solver strategies.Invoking a block factorization of the Jacobian matrix,the Newton-Raphson procedure is reduced to solving two smaller linear systems in the multi-corrector stage.The first is of the elliptic type,indicating that the algebraic multigrid method serves as a well-suited option.The second exhibits a two-by-two block structure that is analogous to the system arising in CFD.Inspired by prior studies,the additive Schwarz domain decomposition method and the block-factorization-based preconditioners are invoked to address the linear problem.Since the number of unknowns matches in both subdomains,it is straightforward to balance loads when parallelizing the algorithm for distributed-memory architectures.We use two representative FSI benchmarks to demonstrate the robustness,efficiency,and scalability of the overall FSI solver framework.In particular,it is found that the developed FSI solver is comparable to the CFD solver in several aspects,including fixed-size and isogranular scalability as well as robustness.本文提出了一个流固耦合的并行计算框架.其中对流体和固体进行了统一的连续介质建模,使之可以利用计算流体力学(CFD)的技术处理结构动力学问题.我们采用了变分多尺度格式进行空间离散.这一数值模型为流体提供了大涡模拟的湍流模型,也为固体提供了不可压缩情形下的压强稳定化机制.为保证鲁棒性,我们采用了全隐式的时间积分,并为此系统性地开发了一套求解策略.该策略是建立在流固的统一描述基础上,通过对雅可比矩阵的块分解,将非线性问题转化为迭代求解一个椭圆型问题和一个鞍点问题.前者使用代数多重网格法作为预条件子;后者受CFD技术启发,考虑了加性Schwarz区域分解法和块分解法两种选项设计预条件子.此外,由于流固网格中各个节点的自由度数保持一致,使得在基于分布式架构的并行化实现中,达到负载均衡变得相对容易.最后,我们以两类典型流固耦合问题为算例展示了流固耦合求解器的性能.结果显示了所提出的求解器在强扩展性、弱扩展性以及鲁棒性等方面具有与隐式CFD求解器接近的性能.

关 键 词：Fluid-structure interaction Monolithic coupling Implicit time integration Iterative methods Vortex-induced vibration 

分 类 号：O35[理学—流体力学]