Fundamentals of overtopping from individual violent water wave impacts

个别猛烈水波冲击翻越的基本原理

• 批准号: EP/D080533/1
• 负责人: Alison Raby
• 金额: $ 22.45万
• 依托单位: Plymouth University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FD080533%2F1
• 关键词: Fundamentals; overtopping; individual; violent; water

Water wave impact on coastal structures such as sea walls, dikes and breakwaters, can lead to water overtopping the structure. This can cause difficulties in the area the structure was built to protect, and possibly damage the structure. Most previous studies of overtopping have examined the total flow of water for a given sea state, and many fewer studies consider individual wave events. These latter have focussed on collecting data on the overtopping event rather than relating it directly to the behaviour of the incident wave, which is the focus of the proposed work. Many types of disturbance and damage are more closely related to individual overtopping events than to the total flow over a longer period. Our recent substantial experimental and numerical modelling work on wave impact on walls, shows the likely importance of relatively rare very violent impacts, and provides a basis for quantitative modelling of wave overtopping, of both violent and more ordinary waves. Greater understanding of these infrequent events will be valuable for both coastal engineering researchers and practitioners alike.The present investigation will again capitalise on the advantages of interactive physical and numerical model studies as a means of gaining new insights into complex wave phenomena. Thus, it is proposed to concentrate in detail on situations of particular scientific interest rather than engage in extensive parametric testing. We note, for example, that there has been little study of the transition between breaking and non-breaking waves on steep beaches / gently sloping structures and expect to find significant differences in swash and overtopping between collapsing and surging breakers on a steep slope. Effects of the structure's geometry, such as different slopes and crest width, will also be examined. The approaching waves will either come over a plane sloping bed or meet a mound at the base of the structure that can trigger plunging or spilling breakers. Experimental measurements of water height, flow rate and pressure will be made. The flow will be numerically modelled by modifying existing programs, one of which includes the compressibility that can be important when air is trapped or entrained by the water. Scaling of results from laboratory measurements to prototype scale can be improved by including such effects. We expect the flow over a structure to depend significantly on its surface roughness, and many protective structures are made of units which are very rough. The study will consider simple roughness elements; for example circular cylinders projecting from the surface. Flow around and over a single roughness element will be related to their overall effect. In the case of the most violent wave impacts we expect that the roughness may also diminish the maximum pressure, by its disturbing effect on the flow.Theoretical work will include analytical study as well as making use of existing numerical programs. Analytical study is a 'blue skies' element of this proposal in that it is rather challenging. It will build on models of swash, since there are very few previous results for overtopping. However, analytical results can be of great value in comprehending different flow regimes.Overall, results from all aspects of this study are to be used to develop improved models of overtopping events that are expected to be useful for designers of coastal structures such as breakwaters and seawalls.

波浪对海堤、堤防、防波堤等海岸结构物的冲击会导致结构物漫顶。这可能会在建造结构以保护的区域中造成困难，并可能损坏结构。大多数以前的研究越浪检查了总流量的水为一个给定的海况，和更少的研究考虑个别波事件。后者的重点是收集有关漫顶事件的数据，而不是将其直接与入射波的行为联系起来，这是拟议工作的重点。许多类型的扰动和损害与个别漫顶事件的关系比与较长时期内的总流量的关系更密切。我们最近大量的实验和数值模拟工作的波浪对墙壁的影响，显示了可能的重要性，相对罕见的非常激烈的影响，并提供了一个基础，定量建模的波浪越浪，暴力和更普通的波浪。更好地了解这些罕见的事件将是有价值的海岸工程研究人员和从业者agree.The目前的调查将再次利用互动的物理和数值模型研究的优势，作为一种手段，获得新的见解复杂的波现象。因此，建议详细集中于具有特别科学意义的情况，而不是进行广泛的参数测试。例如，我们注意到，几乎没有对陡峭海滩/缓坡结构上破碎波和非破碎波之间的过渡进行过研究，并期望在陡坡上的崩塌和涌动破碎波之间发现冲浪和越浪的显著差异。结构的几何形状的影响，如不同的斜率和波峰宽度，也将被检查。接近的波浪要么越过一个平面倾斜的河床，要么在结构物的底部遇到一个土墩，这可能会触发倾翻或溢出的碎浪。将对水的高度、流速和压力进行实验测量。将通过修改现有程序对流动进行数值模拟，其中之一包括当空气被水捕获或夹带时可能很重要的压缩性。将这些效应包括在内，可以改进从实验室测量到原型规模的结果的缩放。我们预期流过结构物的流动在很大程度上取决于其表面粗糙度，许多防护结构物是由非常粗糙的单元组成的。该研究将考虑简单的粗糙度元素;例如从表面突出的圆柱体。单个粗糙度元素周围和上方的流动将与其整体效果相关。在最猛烈的波浪冲击的情况下，我们预计粗糙度也可能通过其对流动的干扰效应来减小最大压力。理论工作将包括分析研究以及利用现有的数值程序。分析研究是这项建议的一个“蓝天”因素，因为它是相当具有挑战性的。它将建立在水冲模型上，因为以前很少有漫顶的结果。然而，分析结果可以理解不同的流regimes.Overall，从本研究的各个方面的结果是非常有价值的开发越浪事件，预计将是有用的沿海结构，如防波堤和海堤的设计师改进模型。

项目成果

The ideal flip-through impact: experimental and numerical investigation

• DOI: 10.1007/s10665-009-9354-3
• 发表时间: 2010-06
• 期刊: Journal of Engineering Mathematics
• 影响因子: 1.3
• 作者: H. Bredmose;A. Hunt-Raby;R. Jayaratne;G. Bullock

Individual violent overtopping events: New insights

个人暴力越轨事件：新见解

• 发表时间: 2008
• 作者: R Jayaratne

Individual violent wave-overtopping events: behaviour and estimation

• DOI: 10.1080/00221686.2018.1555549
• 发表时间: 2019-01
• 期刊: Journal of Hydraulic Research
• 影响因子: 2.3
• 作者: A. Raby;R. Jayaratne;H. Bredmose;G. Bullock

Scaling of wave-impact pressures in trapped air pockets

滞留气穴中波浪冲击压力的缩放

• 发表时间: 2008
• 作者: H Bredmose

Wave height? A study of the impact of wave groups on a coastal structure

波高？

• 发表时间: 2007
• 作者: H Bredmose