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并不十分可靠，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。对近岸物理的进一步研究将导致海岸模型的改进。这项研究将采用实验室实验和数值模型相结合的方法，研究沙洲泥沙运动的驱动机制。以前的研究表明，海浪带中的沉积物运动是由搅动海底沉积物的破碎波和将海床附近的水推向近海的接近破碎的波浪引起的。当这些水向近海流动时，它会带走沉积物。需要进一步的研究来确定这些机制在各种波动条件下的相对重要性。学术价值：这个为期三年的项目将调查与冲浪区沙洲相关的详细泥沙输送过程。试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。将使用几个新型传感器来测量水中的速度、压力和泥沙浓度。实验室和数值试验的结合将提高对模型的理解和预测。更广泛的影响：项目组将开展两项教育外展工作。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响应，每年影响大约350名学生。第二项努力将涉及在哈特菲尔德海洋科学中心为公众制作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方面的培训，每年将有两到三名本科生获得进行实验室实验的实践研究经验。该项目将包括来自荷兰和日本的两名研究人员，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.