MPS-FEM数值分析带自由面的流固耦合问题

Simulation of fluid-structure interaction with violent free surface by MPS-FEM coupled method

随着计算科学的发展,研究人员为探索流固耦合问题的物理机理而提出了众多的数值方法。其中,耦合的移动粒子半隐式方法 MPS(Moving Particle Semi-Implicit method)和有限单元法FEM(Finite Element method)为流固耦合问题的数值仿真工作提供了新的途径。本文所有流场的数值模拟工作均采用课题组自主开发的无网格法求解器MLParticle-SJTU来完成。该求解器在原始的MPS法基础上,对核函数、压力梯度模型、压力泊松方程的求解和自由面判断方式等方面进行了改进。此外,在该求解器框架内,基于FEM法拓展了针对结构场进行求解的功能。首先,对MPS和FEM方法的理论模型及其耦合策略进行了介绍。然后,采用该自研MPS-FEM耦合求解器,数值模拟了溃坝流动对弹性结构的冲击及其相互作用的标准问题。通过将结构变形及自由面波型变化等结果与已发表结果进行对比,验证了该求解器在处理带自由面剧烈变化的粘性流体和柔性变形结构的耦合作用问题上的可行性。

With the development of computational science,various kinds of numerical methods are proposed for the analysis of fluid-structure interaction problems.Recently,a coupled Moving Particle Semi-implicit(MPS)method and Finite Element Method(FEM)is developed as a new approach for FSI problems.In the present study,simulation of fluid fields is carried out by the mesh-free method solver MLParticle-SJTU.The solver is implemented based on the MPS method with improvements on the kernel function,free surface detection,gradient model and Possion's equation of pressure.Furthermore,the module for calculation of structural deformation is developed base on the FEM in the framework of MLParticle-SJTU.In this paper,both MPS and FEM are introduced firstly.Then,the benchmark of the interact between the dam-break flow and the elastic structure is numerically investigated with the help of the presented MPS-FEM coupled solver.Deformation of the elastic structure and evolution of the violent free surface are found to be in good agreement with published results,which shows that the proposed MPS-FEM coupled method is capable of dealing with structural deformation interacting with violent free surface flow.