The orientation, shape, and stability of the Golden Gate sand waves

金门沙波的方向、形状和稳定性

• 批准号: 2130977
• 负责人: Dan Hanes
• 金额: $ 24.09万
• 依托单位: Saint Louis University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-15 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2130977&HistoricalAwards=false
• 关键词: orientation; shape; stability; Golden; Gate

Marine sand waves are like underwater sand dunes. They are found worldwide in shallow marine environments such as tidal inlets and tidal banks. They are also found in some estuaries, submarine canyons, and deep shelf environments. They can be important to navigation and the design and placement of submarine cables, pipelines, and wind power generation facilities. For instance, the unintended exposure of a buried pipeline or cable due to the growth or migration of sand waves can cause catastrophic failure resulting in high costs and destructive ecological impacts. The dynamic migration of sand wave crests into shipping channels can render navigational charts inaccurate and be hazardous to shipping and small boats. This project will use models to study sediment transport in the Golden Gate sand waves, one of the earth’s most striking field of sand waves. The project Broader Impacts include an improved understanding of sand wave dynamics that will help inform sediment management in the region. The project would also support a graduate student.The shape and dynamics of sand waves will be investigated through the integration of multiple existing high resolution field surveys of the Golden Gate sand waves and a calibrated numerical model that incorporates physical processes such as fluid dynamics and sediment transport in coastal regions. The hydrodynamic forcing in the region is due mainly to tides and exhibits a powerful tidal jet due to the flow in and out of San Francisco Bay. In combination with ocean waves this results in a complex and energetic sediment transport patterns and bedform morphodynamics. The goals of this project are to evaluate hypotheses to explain several perplexing observations found in various fields of sand waves worldwide, such as: the asymmetric shapes of individual sand waves and their relation to sand wave migration; the dynamics linking the tidal forcing and the orientation of individual sand wave crests; and the occasional appearance and disappearance of a new sand wave crest within a field of sand waves.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

海洋沙波就像水下的沙丘。它们在世界各地的浅水海洋环境中都有发现，例如潮汐入海口和潮汐滩涂。在一些河口、海底峡谷和深水陆架环境中也发现了它们。它们对导航以及海底电缆、管道和风力发电设施的设计和布置都很重要。例如，由于沙波的生长或迁移，埋在地下的管道或电缆意外暴露，可能会导致灾难性的故障，从而导致高昂的成本和破坏性的生态影响。沙波波峰向航道的动态迁移会使航图不准确，给航运和小船带来危险。该项目将使用模型来研究金门沙波中的泥沙传输，沙波是地球上最引人注目的沙波场之一。该项目更广泛的影响包括更好地了解沙波动力学，这将有助于为该地区的沉积物管理提供信息。该项目还将支持一名研究生。沙波的形状和动力学将通过整合现有的多个对金门沙波的高分辨率现场调查和一个校准的数值模型来研究，该模型结合了沿海地区的流体动力学和泥沙运动等物理过程。该地区的水动力强迫主要是由潮汐引起的，并由于进出旧金山湾的水流而表现出强大的潮汐急流。与海浪相结合，这导致了复杂而充满活力的沉积物运移模式和河床地貌动力学。这个项目的目标是评估假说，以解释在世界各地沙波的不同领域中发现的几个令人困惑的观察结果，例如：单个沙波的不对称形状及其与沙波迁移的关系；将潮汐强迫与单个沙波峰值方向联系起来的动力学；以及在沙波场中偶尔出现和消失新的沙波峰值。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。