管道内流对海洋弹性管振动影响的数值仿真研究

Numerical simulation for effects of pipeline internal flow on vibration of flexible marine pipe

管道的内部流动对于海洋弹性管道而言是一种重要的振动诱发因素,但是目前相关理论较少。运用CFD单双、向流固耦合分析方法,开展了管道内流对海洋弹性管道振动响应影响的研究。通过仅考虑外流的模型试验与数值仿真结果对比分析,发现在外流速度较低时该分析方法与实验结果吻合度较高;在同时考虑内流和外流的工况中,发现内流速度会对管道的振动频率及幅度造成不同程度的影响。在内流速度相对比较小时,管道内流对管道的振动频率及振幅影响都较小;在内流速度相对较大的时候,管道内流对管道横流向振幅及顺流向振型影响较为明显,促使管道在低频段更容易发生共振现象,增加管道的疲劳损伤可能性。该研究关于管内流动对于海洋弹性管道影响的研究,对于弹/柔性管道的结构强度设计和疲劳分析具有一定的参考价值。

Pipeline internal flow is an important vibration-inducing factor for marine elastic pipelines,but at present,there are few related theories.Here,based on the CFD single and double directional fluid-structure interaction analysis method,effects of internal flow propagating along pipe-span on vibration responses of flexible marine pipe/riser were investigated.Contrastive analysis between results of model tests and numerical simulation ones only considering external flow showed that the simulated results using the proposed analysis method and test ones agree better when external flow velocity is low.Under the working condition simultaneously considering internal and external flows,it was shown that different internal flow velocities can have different degrees of influence on vibration frequency and amplitude of flexible marine pipe/riser;when internal flow velocity is relatively small,internal flow has little influence on vibration frequency and amplitude of flexible pipe;when internal flow velocity is relatively large,internal flow has more obvious influence on flexible pipe’s transverse flow vibration amplitude and forward flow vibration mode to make flexible pipe easily have resonance within a low frequency range and increase the possibility of its fatigue damage;the study results can provide a reference for structural strength design and fatigue analysis of elastic/flexible pipelines.