基于ALE有限元法的流固耦合强耦合数值模拟
A PARTITIONED STRONG COUPLING ALGORITH FOR FLUID-STRUCTURE INTERACTION USING ARBITRARY LAGRANGIAN-EULERIAN FINITE ELEENT FORULATION
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摘要: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.Abstract:In this paper a partitioned strong coupling algorith is proposed for the nuerical resolution of different fluid-structure interaction (FSI) probles within the arbitrary Lagrangian-Eulerian finite eleent fraework. The incopressible viscous Navier-Stokes equations are solved by the sei-iplicit characteristic-based split (CBS) schee. Both the generalized rigid-body otion and the geoetrically nonlinear solid are taken into account. The resultant equations governing the structural otions are advanced in tie by the coposite iplicit tie integration schee that allows for a larger tie step size. In particular, the celled-based soothed finite eleent ethod is adopted for the ore accurate solution of the nonlinear elastic solid without coproising the nuerical efficiency. The oving subesh approach in conjunction with the ortho-sei-torsional spring analogy ethod is used to efficiently update the dynaic esh within the fluid doain. A ass source ter (ST) is iplanted into the pressure Poisson equation in the second step of the CBS schee in order to respect the so-called geoetric conservation law. Given the CBS schee, the ST releases the requireent on the differencing schee of the esh velocity. The partitioned iterative solution is easily achieved via the fixed-point ethod with Aitken’s △ 2accelerator. The proposed ethodology is in possession of both the flexibility of coupling individual fields and the progra odularity. The flutter of an H-profile bridge deck and vortex-induced vibrations of a restrictor flap in a unifor channel flow are nuerically siulated by eans of the developed partitioned strong coupling algorith. The nuerical results are in good agreeent with the available data, and deonstrate the desirably coputational accuracy and nuerical efficiency.