Breaking and Runup of Transient Long Waves

2004年苏门答腊-安达曼地震和印度洋海啸发生后，科学家和工程师们一直在共同努力，提高我们对海啸水动力学的了解，并在印度洋和南中国海建立海啸早期预警系统和海啸减灾计划。加强海啸数据的一个有希望的方法是分析沉积物沉积。如果海啸沉积物可以与水深、流速、波浪特征和启动高度相关联，那么沉积物的年代将有助于估计过去海啸的时间和复发间隔。为了建立海啸水动力与大陆架和海岸带泥沙运动过程之间的关系，首先要研究瞬时长波的波浪破碎、湍流产生/消散、底应力演化和升降流过程。根据2004年印度洋海啸期间的观察，很明显，主要的海啸波由几个(1-3)破碎的长波组成。因此，本项目将进行一套以一系列孤立波作为替代引领海啸波的综合实验。主要目标是：1.确定组中波浪数目、入射波浪高度和海滩坡度对启动过程的依赖关系。量化涉及单波和多波的波浪破碎过程，主要是湍流能量和底部剪应力以及相关的耗散，并探索统计稳态行为的可能性。更广泛的影响：这项研究处于几个科学和工程领域的交界处？海洋学、流体力学和海岸工程，并将成为它们之间的桥梁。详细的试验数据将为泥沙悬浮和输运模型中的波浪破碎、底部剪应力和水流湍流的参数化提供必要的信息。因此，这项研究将对建立海啸减灾计划产生更广泛的影响。研究结果还将为今后的实验方向提供指导。该团队将继续与德国布伦瑞格工业大学的H.Oumeraci教授和台湾国立成功大学的H.H.Hwang教授长期合作。尺度效应的某些方面可以通过在他们研究所的大波浪水槽中重复一些所提出的实验条件来研究。该项目将对一名博士生进行实验技术、数据分析和数值方法方面的培训，以便他/她能够进行模型/数据比较。在让工科本科生参与研究和发表技术期刊论文方面，P.I.有着良好的记录，这个项目将为这些领域提供更多的机会。该项目还将支持一名博士后研究员，他将分担监督参与该项目的研究生的责任，并将教授一门本科课程。

After the 2004 Sumatra-Andaman earthquake and Indian Ocean tsunami, scientists and engineers have been working together to improve our understanding of tsunami hydrodynamics and to establish early tsunami warning systems and tsunami hazard mitigation programs in the Indian Ocean and the South China Sea. A promising approach to enhance tsunami data is to analyze the sediment deposits. If tsunami deposits can be correlated with water depth, flow velocity, wave characteristics and run-up heights, the dated sediment deposits will allow estimates of times and recurrence intervals of past tsunamis. In order to establish the relation between tsunami hydrodynamics and sediment transport processes on continental shelf and coastal zones, the first step is to investigate the process of wave breaking, turbulence production/dissipation, bottom stress evolution and run-up/run-down flows of transient long waves. Based on observations during the 2004 Indian Ocean tsunami, it is evident that the leading tsunami waves consisted of several (1 -3) breaking long waves. Therefore, this project will conduct a set of comprehensive experiments in which a series of solitary waves is used as the surrogate leading tsunami waves. The principle objectives are:1. Identifying the dependence of run-up processes on the number of waves in the group, the incident wave heights, and beach slope.2. Quantifying the wave breaking processes involving single and multiple waves, primarily the turbulent energy and the bottom shear stress and associated dissipation and exploring the potential for statistically steady-state behavior.The Broader Impacts:This research is at the interface between several fields of science and engineering ? oceanography, fluid mechanics, and coastal engineering and will serve as a bridge among them. The detailed experimental data will provide the necessary information for the parameterization of wave breaking, bottom shear stress and flow turbulence in the sediment suspension and transport models. Therefore, the study will have a much broader impact on the establishment of tsunami hazard mitigation programs. The results will also provide guidance for future direction of experiments. The team will continue its long term collaborations with Prof. H. Oumeraci of the Technical University of Braunschweig, Germany and Prof. H. H. Hwang of the National Cheng Kung University, Taiwan. Certain aspects of scale effects can be investigated by repeating some of the proposed experimental conditions in the large wave flumes in their institutes. The project will train one PhD student in experimental techniques, data analysis and numerical methods so that he/she will be capable of performing model/data comparisons. The P.I. has had a good record of involving engineering undergraduate students in research and in publishing technical journal papers, and this project will provide further opportunities along those lines. The project will also support a postdoctoral researcher who will share the responsibility on supervising the graduate student working on the project and will also teach an undergraduate course.