Collaborative Research: Large-scale Laboratory Investigation and Numerical Modeling of Sheet Flow Sediment Transport Dynamics across a Surf Zone Sand Bar

目前对海滩侵蚀事件的模型预测不是很可靠，因为它们没有考虑到近岸环境中发生的所有复杂的物理过程。近岸物理的进一步研究将导致沿海模式的改进。本研究将采用实验室实验和数值模型相结合的方法来研究驱动沉积物穿越沙洲的机制。先前的研究表明，冲浪区的沉积物运动是由破碎的海浪搅动海底的沉积物和接近破碎的海浪推动近海床附近的水引起的。当这些水向近海移动时，它会带走沉积物。需要进一步的研究来确定这些机制在不同波浪条件下的相对重要性。知识价值：这个为期三年的项目将调查与冲浪带沙洲相关的沉积物运输过程的细节。实验将在具有固定海滩形式和两个沙坑的大型波浪水槽中进行。几个新型传感器将被用来测量水中的流速、压力和沉积物浓度。实验室和数值实验的结合将导致对模型的理解和预测的改进。更广泛的影响：项目团队将开展两项教育推广工作。第一项工作将使用便携式波浪水槽向中学生演示海滩剖面对风暴和海平面上升的反应，每年影响大约350名学生。第二项努力将包括在哈特菲尔德海洋科学中心为公众开发一个关于海岸侵蚀的永久性教育展览。在这个项目中，三名博士生将接受最先进的实验室和近岸动力学数值方法的培训，每年两到三名本科生将获得进行实验室实验的实践研究经验。该项目将包括两名来自荷兰和日本的研究人员，以促进国际交流。研究生将有机会参观两国的实验室。

Currently model predictions of beach erosion events are not very reliable because they do not account for all the complex physical processes that occur in the nearshore environment. Further study of nearshore physics will lead to improvements in coastal models. This study will investigate mechanisms that drive sediment transport across sand bars using a combination of laboratory experiments and numerical models. Previous studies have shown that movement of sediment in the surf zone is caused by breaking waves that stir up sediment on the seafloor and near-breaking waves that drive water near the bed offshore. As this water moves offshore, it takes sediment with it. Further study is required to determine the relative importance of these mechanisms under various wave conditions. Intellectual merit: This three-year project will investigate the detailed sediment transport processes associated with a surf-zone sand bar. Experiments will be conducted in a large-scale wave flume with a fixed beach form and two sand pits. Several novel sensors will be employed to measure velocity, pressure, and sediment concentration in the water. The combined laboratory and numerical experiments will lead to improvements in understanding and model prediction. Broader Impacts: The project team will conduct two educational outreach efforts. The first effort will use a portable wave flume to demonstrate storm and sea level rise response of the beach profile to middle school students, impacting approximate 350 students per year. The second effort will involve developing a permanent educational display on coastal erosion for the general public at the Hatfield Marine Science Center. Three PhD students will be trained in state-of-the-art laboratory and numerical approaches to near-shore dynamics in this project, and two to three undergraduate students per year will gain hands-on research experience in conducting laboratory experiments. This project will foster international exchange by including two researchers from The Netherlands and Japan. Graduate students will be given the opportunity to visit laboratories in both countries.