海底子母管线在规则波作用下的数值研究

采用三步有限元法离散N-S方程,建立了数值波浪水槽模型。数值研究了规则波作用下海底子母管结构的水动力特性。对海底子母管线所受波浪力的数值结果与物模实验结果进行比较。基于该数值模型,还考察了不同的子母管间相对缝隙G/D(0.1,0.25,0.5,0.75)对海底子母管线水动力特性的影响。分析得到了不同G/D下海底子母管线的涡脱落特性以及管线水动力系数随G/D的变化规律。结果表明,数值结果和实验结果吻合较好,该数值波浪水槽模型可用来计算波浪作用在海底子母管线上的水动力。关于不同G/D,得到了2种不同的涡脱落模式,在G/D较小(0.1,0.25)时,为"反相同步脱落"模式,在G/D较大(0.5,0.75)时,为"同相同步脱落"模式。

Numerical study of submarine piggyback pipeline under regular wave action

A numerical wave flume model was established,in which the Navier-Stokes equation was dispersed using the three-step finite element method.Then the hydrodynamic characteristics of the submarine piggyback configuration under regular wave action were numerically studied.The numerical results for wave forces on submarine piggyback pipeline were compared with the experimental results.Based on this numerical model,the effect of the spacing ratios between the small and the large pipeline G/D(0.1,0.25,0.5,0.75)on the hydrodynamic characteristics of the submarine piggyback pipeline was also investigated.The vortex shedding characteristics of the piggyback pipeline about different G/D and the variation of hydrodynamic coefficients of the pipeline with G/D were presented in this paper.The results show that both numerical and experimental results are in good agreement,and the numerical wave flume model can be applied to predict the hydrodynamic forces on the submarine piggyback pipeline under wave action.Two different vortex shedding patterns are found about different G/D.One is the"anti-phase-synchronized"pattern for G/D=0.1,0.25,the other is the"in-phase-synchronized" pattern for G/D=0.5,0.75.