Internal solitary wave-induced sediment resuspension and offshore infrastructure loading

内部孤立波引起的沉积物再悬浮和海上基础设施负荷

• 批准号: RGPIN-2017-04568
• 负责人: Boegman, Leon
• 金额: $ 2.99万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=749307
• 关键词: Internal; solitary; wave; induced; sediment

Internal solitary waves are ubiquitous features of the coastal ocean. Propagating on subsurface density interfaces, these waves have ~1 km wavelengths, ~100 m amplitudes and >1 m s-1 currents; thereby transporting significant energy shoreward from their offshore generation sites. Where the internal solitary waves shoal, the associated near-bed turbulence re-suspends and re-distributes bottom sediment, pumping organic matter, nutrients and contaminants vertically through the water-column. The suspended sediment creates nepheloid (turbidity) layers that are 100s of m thick and forms immense dune fields with ~100 m wavelengths on the ocean floor. Internal solitary waves also apply hazardous loads to subsea infrastructure, with wave impacts leading to broken drill strings and anchor chains, lost remote operated vehicles and listing of rigs, causing millions of dollars in repositioning costs and lost revenue. Moreover, present subsea pipeline design criteria require costly secondary stabilization and increased pipeline wall thickness in solitary wave breaking zones. Reduced uncertainty in estimation of the associated design criteria will save $10s of millions.The proposed research will train 4 PhD, 6 MSc and 5 undergraduate students, who will perform laboratory experiments and numerical simulations to investigate internal solitary wave shoaling in the coastal ocean. They will: (1) develop models to parameterize the dynamic effects of internal solitary waves on sediment resuspension and quantify the associated sediment transport; (2) determine whether bottom roughness is preventing high-resolution computer simulations from reproducing laboratory-generated solitary waves; (3) measure the design loads (force, torque and stress) applied by internal solitary waves to offshore oil and gas infrastructure (vertical columns and horizontal pipelines).This research will develop solutions to address critical needs of (1) Oceanographers, who require laboratory data to predict wave resuspension and breaking locations in the field; (2) Numerical Modellers, who require laboratory data for model validation; (3) Government Agencies that manage fisheries, navigation and develop building codes; (4) aspiring MetOcean engineers, who require advanced graduate training to work in the oceanography and resource sectors; and (5) Resource and Engineering Companies that manage rigs and lay pipeline in internal solitary wave impacted waters, using costly secondary stabilization and conservative pipeline wall thicknesses.

内孤立波是沿海海洋普遍存在的特征。 这些波在地下密度界面上传播，波长约为 1 km，幅度约为 100 m，电流 >1 m s-1；从而将大量能源从海上发电站输送到岸上。 在内部孤立波浅滩的地方，相关的近床湍流重新悬浮并重新分布底部沉积物，将有机物、营养物和污染物垂直地泵入水柱。 悬浮沉积物形成了数百米厚的霞云（浊度）层，并在海底形成了波长约为 100 米的巨大沙丘场。 内部孤立波还会对海底基础设施施加危险载荷，波浪冲击会导致钻柱和锚链断裂、遥控车辆丢失和钻机倾斜，造成数百万美元的重新定位成本和收入损失。 此外，目前的海底管道设计标准需要昂贵的二次稳定以及增加孤波破碎区域的管道壁厚。减少相关设计标准估计的不确定性将节省数十百万美元。拟议的研究将培训 4 名博士生、6 名硕士生和 5 名本科生，他们将进行实验室实验和数值模拟，以研究沿海海洋中的内部孤立波浅滩。 他们将：（1）开发模型来参数化内部孤立波对沉积物再悬浮的动态影响，并量化相关的沉积物迁移； (2) 确定底部粗糙度是否妨碍高分辨率计算机模拟再现实验室生成的孤立波； (3) 测量内部孤立波对海上石油和天然气基础设施（垂直柱和水平管道）施加的设计载荷（力、扭矩和应力）。本研究将开发解决方案，以满足 (1) 海洋学家的关键需求，他们需要实验室数据来预测现场的波浪重悬和破裂位置； (2) 数值建模者，需要实验室数据进行模型验证； (3) 管理渔业、航海和制定建筑规范的政府机构； (4) 有抱负的海洋气象工程师，需要高级研究生培训才能在海洋学和资源领域工作； (5) 在受孤立波影响的水域中管理钻井平台和铺设管道的资源和工程公司，使用昂贵的二次稳定和保守的管道壁厚。