针对不同流固耦合问题,提出一种基于任意拉格朗日--欧拉(ALE)有限元技术的分区强耦合算法.运用半隐式特征线分裂算法求解ALE描述下的不可压缩黏性流体Navier-Stokes方程.分别考虑一般平面运动刚体和几何非线性固体,采用复合隐式时间积分法推进结构运动方程,故可选用较大时间步长;进一步应用单元型光滑有限元法求解几何非线性固体大变形,获得更精确结构解且不影响计算效率.运用子块移动技术结合正交--半扭转弹簧近似法高效更新流体动网格;同时将一质量源项引入压力泊松方程满足几何守恒律,无需复杂构造网格速度差分格式.采用简单高效的固定点法配合Aitken动态松弛技术实现各场耦合,可灵活选择先进单场求解技术,具备较好程序模块性.运用本文算法分别模拟了H型桥梁截面颤振问题和均匀管道流内节气阀涡激振动问题.研究表明,数值结果与已有文献数据吻合,计算精度和求解效率均令人满意.%In this paper a partitioned strong coupling algorithm is proposed for the numerical resolution of different fluid-structure interaction(FSI)problems within the arbitrary Lagrangian-Eulerian finite element framework.The incom-pressible viscous Navier-Stokes equations are solved by the semi-implicit characteristic-based split(CBS)scheme. Both the generalized rigid-body motion and the geometrically nonlinear solid are taken into account. The resultant equations governing the structural motions are advanced in time by the composite implicit time integration scheme that allows for a larger time step size. In particular,the celled-based smoothed finite element method is adopted for the more accurate solution of the nonlinear elastic solid without compromising the numerical efficiency. The moving submesh approach in conjunction with the ortho-semi-torsional spring analogy method is used to efficiently update the dynamic mesh within the fluid domain. A mass source term(MST)is implanted into the pressure Poisson equation in the second step of the CBS scheme in order to respect the so-called geometric conservation law. Given the CBS scheme,the MST releases the requirement on the differencing scheme of the mesh velocity. The partitioned iterative solution is easily achieved via the fixed-point method with Aitken's?2accelerator. The proposed methodology is in possession of both the flexibility of coupling individual fields and the program modularity. The flutter of an H-profile bridge deck and vortex-induced vibra-tions of a restrictor flap in a uniform channel flow are numerically simulated by means of the developed partitioned strong coupling algorithm. The numerical results are in good agreement with the available data,and demonstrate the desirably computational accuracy and numerical efficiency.
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