Numerical simulation of vortex-induced vibration of long flexible risers using a SDVM-FEM coupled method
Numerical simulation of vortex-induced vibration of long flexible risers using a SDVM-FEM coupled method
复制标题
采用 SDVM-FEM 耦合方法对长柔性立管涡激振动进行数值模拟
DOI：
10.1016/j.oceaneng.2018.12.006
复制
发表时间：
2019
影响因子：
5
通讯作者：
Wang Jiasong
中科院分区：
文献类型：
--
作者：
Lin Ke;Wang Jiasong
This paper presents a grid-independent numerical methodology that couples the strip theory based discrete vortex method (SDVM) with the finite element method (FEM) to simulate the vortex-induced vibration (VIV) of a long flexible vertical riser. Based on the strip theory, a three-dimensional flow filed is approximately simulated by a series of computational ‘flow strips’. A Lagrangian discrete vortex method is employed to numerically solve the unsteady vorticity transport equations of each ‘flow strip’. The flexible riser is modelled as a tensioned Bernoulli-Euler beam with the dynamical equation solved by the finite element method in time domain. The two-dimensional DVM code is firstly validated for the VIV simulation of a rigid cylinder that was experimentally studied by Khalak and Williamson (1996). Referring to two typical experimental configurations of Lehn (2003) and Chaplin et al. (2005), the VIV of a long flexible riser immersed in a uniform and stepped incoming flow are numerically simulated, respectively. A good agreement was achieved through detailed comparisons between the present numerical prediction and the experimental data, including the structural in-line and cross-flow VIV response modes, root mean square amplitudes and the dominant frequency. The occurrence of standing and travelling wave responses, dual resonance between in-line and cross-flow motions and figure-eight trajectory are reported. The wake patterns corresponding to two response waves are also presented and investigated. Related to structural local vibration amplitude, two principle vortex patterns resembling the ‘2S’ and ‘2P’ modes are identified in the wake. The standing wave component of structural response determines the vortex shedding pattern. The travelling wave component affects the spanwise vortices shedding at different phases.
