Modelling Extreme Free-Surface Flows: applications to breaking waves, wave-structure and wave-vessel interactions

拟议的研究涉及极端自由表面流动的描述与应用在深水离岸和浅水沿海地区。这项工作将涉及开发一个新的数值模型，适用于描述大型水面波浪及其与固定结构和浮动船只的相互作用。连接这些流动的关键特征将是波浪破碎的发生;涉及水面的破碎、空气的夹带和高度湍流区域的快速发展。从实际角度来看，这种流动极其重要，因为它们与最高（限制）水面高程、最大水颗粒速度和最大施加流体载荷相关。因此，它们直接关系到各种海洋结构物和船舶的设计。为了模拟这种流动，并在这样做的过程中提供更好的物理理解，新的数值模型将联合收割机两个非常不同的建模程序的优点：边界元法应用于波浪破碎开始前和光滑粒子流体动力学应用于破碎和破碎后的流体流动。通过结合这些程序，所提出的方法将寻求创建一个强大的和准确的模型，能够描述范围广泛的自由表面流;特别注意的是那些方面的波结构和波船相互作用的设计是至关重要的，不能通过现有的解决方案proceeds.The模型预测将验证新的实验室观测。这将涉及使用比例物理模型试验，并将考虑各种实际重要的流体流动，包括：（一）破碎波，包括大规模倾覆和溢出波;（二）波浪-结构相互作用中的高度非线性效应，包括高频波浪散射、流体向上喷射到很高的高度产生甲板波浪载荷的垂直喷射，以及垂直柱和甲板结构上的波浪撞击;（iii）波浪与船舶的相互作用，特别是绿色水淹没和巨大冲击力的发生。在解决这些问题时，结合实验和数值研究将寻求对这些事件发生的时间和原因提供新的物理理解，以评估其实际意义，并确定如何在工程实践中最好地模拟它们。拟议的工作与流体力学中的广泛问题有关，特别适用于海洋结构的有效设计和安全操作。该提案包括三个主要行业从业人员的直接支持。该项目还将与可再生能源行业有关。由于对将海上风电场定位在大风区域以及因此大的波浪活动区域的兴趣，这种结构非常容易受到大规模波浪破碎和相关联的冲击力的影响。航运业也将受益于这一项目：新的模型提供信息，以改进船舶的设计和/或安全操作，提高生存能力，并限制油轮对环境造成大规模影响和损害的可能性。最后，这项工作也有一个真正的多学科的贡献，超越了沿海/近海/肚脐架构的界限，在这个意义上，打破了水面（特别是空气夹带）的海气相互作用的影响一般，特别是质量交换（CO2吸收）。这些问题对于研究海洋表面转移过程的海洋学家至关重要，是气候变化建模的一个关键要素。

The proposed research concerns the description of extreme free-surface flows with applications in both deep water offshore and the shallow water coastal locations. The work will involve the development of a new numerical model appropriate to the description of large surface water waves and their interaction with both fixed structures and floating vessels. The key feature linking these flows will be the occurrence of wave breaking; involving the break-up of the water surface, the entrainment of air and the rapid development of areas of highly turbulent flow. From a practical perspective such flows are extremely important because they are associated with the highest (limiting) water surface elevations, the largest water particle velocities and the maximum applied fluid loads. As a result, they are directly relevant to the design of all manner of marine structures and vessels.In order to simulate such flows, and in so doing provide improved physical understanding, the new numerical model will combine the advantages of two very different modelling procedures: a Boundary Element Method applied before the onset of wave breaking and Smooth Particle Hydrodynamics applied to the breaking and post-breaking fluid flow. By combining these procedures the proposed method will seek to create a robust and accurate model capable of describing a wide range of free-surface flows; particular attention being paid to those aspects of wave-structure and wave-vessel interactions that are critical for design and cannot be described by existing solution procedures.The model predictions will be validated against new laboratory observations. This will involve the use of scaled physical model tests and will consider a wide range of practically important fluid flows including:(i) Breaking waves, including both large-scale over-turning and spilling waves;(ii) Highly nonlinear effects in wave-structure interaction, including high-frequency wave scattering, vertical jetting where fluid is projected upwards to very high elevations creating wave-in-deck loads, and wave slamming on both vertical columns and the deck structure;(iii) Wave-vessel interactions, particularly the occurrence of green water inundation and large impact forces.In tackling these problems, the combined experimental and numerical studies will seek to provide new physical understanding of when and why these events occur, to assess their practical implications and to identify how they can best be modelled in engineering practice.The proposed work is relevant to a wide range of problems in fluid mechanics, with particular application to the effective design and safe operation of marine structures. Direct support from three key industrial practitioners is incorporated within the proposal. The project will also be relevant to the renewable energy industry. With interest in locating offshore wind farms in areas of high wind and therefore large wave activity, such structures are very susceptible to large-scale wave breaking and the associated impact forces. The shipping industry will also benefit from this project: the new model providing information to improve the design and/or safe operation of vessels to both increase survivability and, in the case of oil tankers, limit the potential for large-scale environmental impact and damage. Finally, the work also has a truly multi-disciplinary contribution, beyond the coastal/offshore/navel architecture boundaries, in the sense that the break-up of the water surface (specifically the entrainment of air) has implications for air-sea interactions in general, and mass exchange (CO2 absorption) in particular. Such issues are of fundamental importance to oceanographers studying the transfer processes at the ocean surface and contribute a key element to climate change modelling.