Abstract

Submarine pipelines are likely to be impacted by frequently catastrophic landslides, resulting in broken pipelines and causing irreversible economic losses; however, because pipelines located in deep-sea environments are simply laid atop the seabed, effective protective measures have not yet been proposed. In this paper, a pipeline with a uniform distribution of honeycomb holes on the surface, namely, a honeycomb-hole submarine pipeline, is discussed and optimized in detail. A computational fluid dynamics (CFD) approach is verified and improved several times and then applied to conduct 120 numerical simulations for 12 types of suspended submarine pipelines under 10 conditions covering the Reynolds number range required by the project conditions. First, the typical characteristics of the impact forces acting on pipelines in a seawater environment are systematically investigated, and the peak drag force is isolated as the most dangerous load caused by a landslide impact. Second, according to the formation and reduction mechanism of the drag force, it is proposed that a honeycomb-hole submarine pipeline can effectively delay the separation of the boundary layer, reduce the impact velocity, prolong the arrival time, and decrease the differential pressure drag force. Finally, two normalized parameters, the depth ratio and area ratio, are established to develop an optimization design methodology, and the optimal design values of honeycomb-hole pipelines are achieved under the support of limited data. This work presents a protective technology for submarine pipelines and provides new insights into the response of fluid-structure interactions.

摘要

海底管道容易受到频繁发生的灾难性山体滑坡的影响，导致管道破裂，造成不可挽回的经济损失；然而，由于位于深海环境中的管道只是简单地铺设在海床上，因此尚未提出有效的保护措施。本文对一种表面蜂窝孔分布均匀的管道，即蜂窝孔海底管道进行了详细的讨论和优化。一种计算流体动力学（CFD）方法经过多次验证和改进，然后应用于涵盖项目条件所需雷诺数范围的10种条件下的12种悬浮海底管道进行120次数值模拟。第一的，系统研究了海水环境中作用在管道上的冲击力的典型特征，并将峰值阻力作为滑坡冲击引起的最危险载荷进行了隔离。其次，根据阻力的形成和减小机理，提出蜂窝孔海底管道可以有效延迟边界层分离，降低冲击速度，延长到达时间，降低压差阻力。力量。最后，建立深度比和面积比两个归一化参数，建立优化设计方法，在有限数据的支持下获得蜂窝孔管道的优化设计值。