高精度深海立管涡激振动数值预报

High accuracy deep sea riser VIV numerical analysis

针对深海立管涡激振动问题,提出一种高精度的数值预报方法。基于三维Common-Refinement方法,研究了离散后不可压缩流体与非线性超弹性体的非重叠子区域之间的耦合接触面的空间插值。采用Petrov-Galerkin有限元法离散不可压缩流体,并对大变形弹性结构体使用连续Galerkin有限元法行离散。同时使用任意的Lagrangian-Eulerian(ALE)方法处理流固网格的大幅变形,并且采用全解耦的隐式分区方法去分别求解流体域和结构域。基于Common-Refinement方法的空间插值的准确性和可靠性,满足两者之间液体和弹性体耦合界面间牵引力的平衡条件。本方将Common-Refinement方法应用深海立管涡激振动问题,并与文献进行了对比。求解结果表明:本文方法在海洋工程流固耦合问题中具有足够的准确性和可靠性。

This work proposes a high-precision numerical prediction method to solve the vortex-induced vibration(VIV) problem. The three-dimensional(3-D) Common Refinement method(CRM) is applied to investigate the spatial interpolation for the coupling contact surface between the non-overlapping subdomains of a discretized incompressible fluid and a nonlinear super-elastic structure. Incompressible fluid flow is discretized through the Petrov-Galerkin finite element method, and the large deformation elastic structure is discretized by using the continuous Galerkin finite element method. An arbitrary Lagrangian-Eulerian formulation is used to treat the large deformation of the fluid-solid grid, and the fluid and solid domains are solved through fully decoupled implicit partitioning procedures. The accuracy and reliability of the spatial interpolation of the CRM to meet the balanced condition is adopted. The result reveals that the common refinement grid across nonmatching fluid-structure grids enables the accurate transfer of the physical quantities across the fluid-structure system. Finally, CRM is applied to the deep-sea riser VIV problem, and the results of this study are then compared with those of relevant works. Results illustrate that the presented method can accurately and reliably solve the fluid-solid coupling problem encountered in marine engineering.