摘要
为保护海底管线避免冲刷,对海底管线局部冲刷的临界条件进行研究是十分有必要的。基于海床多孔介质假设,通过添加源项方法来实现海床泥沙颗粒对水流的阻滞作用,建立了海底管线周围水动力场-渗流场耦合数值模型。利用前人数值试验结果对该数值模型进行了验证,在此基础上基于边界造波法和VOF方法对波浪作用下海底管线周围水动力场-渗流场进行了联合数值求解。分析了波浪KC数、相对埋深e/D对管线两端压差的影响,研究了管涌出口处水力梯度的变化规律。研究发现管线两端压差和渗流水力梯度随着KC和相对埋深e/D的增大而减小。管线冲刷的临界无量纲流速随着KC和相对埋深的增大而增大,并通过曲线拟合建立了一个用于计算管线冲刷无量纲流速的经验公式,为实际工程中海底管线的防护提供了重要的技术支持。
It is absolutely essential to study scour onset beneath submarine pipelines for pipeline protection. In this paper a new hydrodynamic-seepage fields coupled numerical model was developed, assuming that the sandy bed was porous media. Sand flow resistance in a sandy bed was implemented by adding an adequate source in the mo- mentum equation. The numerical model was verified by numerical experiments, and on this basis, the hydrodynam- ic-seepage fields around submarine pipeline under wave action were solved based on the boundary wave generation and volume of fluid （VOF） methods. The effects of wave KC and relative buried depth e/D on pressure difference between upstream and downstream points of pipe were analyzed respectively and the hydraulic gradient at the seep- age exit was studied. In addition, the dimensionless critical velocities of critical condition in cases of different KC and e/D were obtained. It was found that the pressure difference decreases with increasing KC and relative buried depth e/D while the dimensionless critical velocity of critical condition increases with increasing KC and e/D. Also, an empirical fitted formula to calculate the critical condition for scour below submarine pipelines under wave action is given, which is significant foreffective protection of submarine pipelines in practical engineering projects.
出处
《哈尔滨工程大学学报》
EI
CAS
CSCD
北大核心
2015年第11期1433-1437,共5页
Journal of Harbin Engineering University
基金
国家自然科学基金资助项目(41376099)
浙江省科技厅条件建设资助项目(2013F10031
2014F10036)
浙江省博士后科研择优资助项目(BSH1502052)
水利部公益性行业科研专项基金资助项目(201401010)
关键词
海底管线
多孔介质
冲刷
临界条件
边界造波法
VOF方法
submarine pipe line
porous media
scour
critical condition
boundary wave generation method
VOF method
