海底管道管跨段在内外流体作用下的竖向动力特性研究

Study on the Cross-Flow Dynamic Characteristics of a Submarine Free SpanPipeline Subjected to Internal and External Flow

根据在复杂的海洋环境条件下 ,管道的动力特性受到内外流体的综合作用影响 ,呈现与陆地管道不同的特点。研究了结构受到外界流体所产生的涡激作用 ,同时考虑管内恒定流的影响 ,利用有限元方法对海底管道管跨段竖向振动的微分方程进行求解。在此基础上得出了管跨段在不同外流流速情况下 ,内流流速与结构动力响应幅值的关系及其对管跨段振动频率的影响 ,并进一步探讨了管跨失稳时的极限管内流速与跨长的关系 ,这些结论对于海底管道设计具有一定实际指导意义。

Under the hostile ocean environment, the dynamic characteristics of a submarine free span pipeline would be quite different from those of a pipeline on land as a result of the combined influence of internal and external fluids. This paper investigates the effect of vortex induced by external current on structures, meanwhile it takes the steady inner flow into consideration and solves the cross-flow differential function of a submarine free span pipeline by means of the finite element method. The relationship between the inner flow velocity and the resonant amplitude of a free span pipeline under different external current speeds is achieved by the numerical study. Then the effect of the internal current speeds on the frequency of a free span pipeline is discussed. Furthermore, the relationship between the critical internal velocity in the case of instability and the corresponding length of a free span is explored in this paper. The conclusion from the research could provide some useful information for submarine pipeline design.