Collaborative Research: Rip Current Dynamics in a Complex Beach Environment

合作研究：复杂海滩环境中的激流动力学

• 批准号: 0727376
• 负责人: James Kirby
• 金额: $ 22.92万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-10-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0727376&HistoricalAwards=false
• 关键词: Collaborative; Research; Rip; Current; Dynamics

Over the past three decades, field experiments have been performed primarily on beaches with relatively simple planforms (straight and parallel contours). These observations were used to verify depth-averaged wave-driven flow models. To a large extent, the local vertical flow structure in alongshore currents and undertow is understood on beaches lacking alongshore variability. However, straight and parallel bottom contours, or simple beach planforms are not a stable morphodynamic beach state, with complex morphology being the norm. This has motivated experiments on complex beaches. Rip currents, transient rip currents, and surf zone eddies co-exist with gravity waves (incident sea-swell and infragravity) in the surf zone, yet their importance and dynamic coupling have gone unrecognized owing to a lack of comprehensive field measurements and numerical model verification on complex morphologic beach systems. For this project, we will participate in a European field experiment aimed at understanding nearshore circulation associated with rip current morphology. A multi-institutional and international field experiment is planned for the spring of 2008 at Truc Vert Beach, France. This beach features an energetic wave climate, strong tidal modulation, and a typically complex beach planform composed of crescentic bars, rip channels, and an inter-tidal zone with ridge and runnel systems. The scientific objectives are to examine the nearshore mixing, mean flow patterns, sediment transport, and bathymetric coupling of low frequency rip current pulsations through observations and advance numerical modeling. Imbedded in cross- and alongshore fixed instrument arrays, new Lagrangian observations using a fleet of inexpensive surf zone drifters will provide vital spatial maps of circulation patterns. The dense Eulerian and Lagrangian observations along with the numerical modeling efforts will be used to evaluate the cross- and alongshore distribution of momentum and energy in the nearshore, the influence sedimentation patterns and transport, and the mixing of water masses in this heavily utilized segment of the ocean.The broader impacts of the research include predicting location, persistence, and strength of rip currents for swimmer safety, understanding nearshore mixing, modeling dispersion of pollutants, and anticipating shoreline and dune erosion. This type of beach planform is more complex than any that has been previously studied in a comprehensive fashion, and thus the proposed data will be unique among available data sets obtained anywhere in the world. Among the broader imparts, this effort will provide hands-on research and thesis opportunities for up to six graduate students.

在过去的三十年中，现场实验主要是在具有相对简单的平面形式（直和平行轮廓）的海滩上进行的。这些观察结果用于验证深度平均波动流动模型。 在很大程度上，在缺乏沿岸变异性的海滩上了解了沿岸电流和境内的局部垂直流结构。 但是，直且平行的底部轮廓或简单的海滩平面形成不是稳定的形态学海滩状态，复杂的形态是常态。这激发了关于复杂海滩的实验。冲浪区域中与重力波（入射海静河和北极扇出）并存的裂口电流，瞬态撕裂电流和冲浪区涡流在冲浪区域共存，但由于缺乏全面的田间测量和对复杂的形态海滩系统上的数值模型验证，它们的重要性和动态耦合尚未得到认识。对于这个项目，我们将参加旨在了解与RIP当前形态相关的近海循环的欧洲现场实验。 计划在2008年春季在法国Truc Vert海滩举行多个机构和国际实地实验。该海滩具有充满活力的波浪气候，强烈的潮汐调制，以及一个典型的复杂海滩平面形式，由新月形杆，撕裂​​通道和带脊和跑步系统的潮汐区组成。科学目标是通过观察和提前的数值建模来检查近海混合，平均流动模式，沉积物传输以及低频RIP电流搏动的测深耦合。嵌入在跨境和沿岸固定仪器阵列中，使用廉价的冲浪区域漂移机队的新拉格朗日观察将提供循环模式的重要空间图。茂密的欧拉尔和拉格朗日观察以及数值建模工作将用于评估近岸动量和能量的跨境和沿岸分布，影响沉积模式和运输的影响，以及在这种大量使用的大海中，水质量的混合。建模污染物的分散体，并预测海岸线和沙丘侵蚀。这种类型的海滩平面形式比以前以全面研究的任何研究更为复杂，因此，在世界各地获得的可用数据集中，提出的数据将是唯一的。在更广泛的授权中，这项工作将为多达六名研究生提供动手研究和论文的机会。