CAREER: Experimental and Theoretical Investigation of Sediment Supply and Sorting in Meandering Rivers

职业：曲流河流泥沙供应和分类的实验和理论研究

• 批准号: 1455259
• 负责人: Peter Nelson
• 金额: $ 51.08万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-15 至 2021-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1455259&HistoricalAwards=false
• 关键词: CAREER; Experimental; Theoretical; Investigation; Sediment

A non-technical description of the project's broader significance and importanceMeandering river channels are one of the most iconic features of the landscape and the migration of these large bends in rivers are a direct concern to communities and landowners along the flood plain. The mechanisms of meander formation and migration have long attracted the attention of scientists and engineers. There remain, however, considerable gaps in knowledge of these channels, especially regarding the dynamic interactions among sediment supply, grain-size of river bed sediment, and the river-bed topography. The scientific focus of this CAREER project is to explore these relationships using laboratory flume experiments, analytical theory, and numerical modeling. The results of this research will have applications to pressing societal issues such as flood protection, stream channel maintenance, river restoration, and dam removal. The research will be integrated with an educational and outreach program designed to introduce K-12 students and the public to important issues in river science and management, and to improve the educational experience of undergraduate and graduate engineering students.A technical description of the projectThe scientific objectives of this project are 1) to investigate how channel curvature affects equilibrium patterns of bed topography and surface sorting, 2) to examine how changes in sediment supply affect sorting and bed topography in meandering channels, and 3) to explore the interactions of free and forced bars in meandering channels of mixed grain size sediment and variable sediment supply. A comprehensive suite of flume experiments will be conducted to test several hypotheses. The first experiments will use detailed flow and sediment transport measurements to examine the mechanisms controlling equilibrium conditions at different meander curvatures. The second experiments will focus on questions related to sediment supply effects on bar-pool morphology and the interactions between free and forced bars in curved channels. In conjunction with Italian colleagues, the project will develop a theoretical model for river meandering that incorporates sediment supply and grain sorting. This new model, along with two-dimensional numerical models, will extend knowledge of processes of meandering channels beyond the scales achievable in the laboratory.

对该项目更广泛的意义和重要的河流渠道的非技术描述是景观的最具标志性特征之一，河流中这些大弯道的迁移是沿洪水平原的社区和土地所有者的直接关注。蜿蜒形成和迁移的机制长期以来一直吸引了科学家和工程师的注意。但是，在这些渠道的知识方面仍然存在很大的差距，尤其是关于沉积物供应之间的动态相互作用，河床沉积物的晶粒大小和河床地形。该职业项目的科学重点是使用实验室水槽实验，分析理论和数值建模探索这些关系。这项研究的结果将在紧迫的社会问题上应用，例如防洪，河道维护，河流修复和拆除大坝。这项研究将与旨在向K-12学生和公众介绍河流科学和管理中的重要问题的教育和外展计划融合，并改善本科和研究生工程专业的学生的教育经验。该项目的科学目标是该项目的技术描述是1），以研究渠道频道供应如何影响床上的平衡和表面上的平衡，以调查频道的平衡和表面上的平衡。 3）在混合晶粒尺寸沉积物和可变沉积物供应的蜿蜒通道中探索自由和强制棒的相互作用。将进行全面的水槽实验套件以检验几个假设。第一个实验将使用详细的流量和沉积物传输测量来检查控制不同曲折曲率下平衡条件的机制。第二个实验将重点放在与沉积物供应对棒池形态的影响以及弯曲通道中自由条和强制条之间的相互作用有关的问题。与意大利同事一起，该项目将开发出一种理论模型，用于融合沉积物的供应和谷物分类。这个新模型以及二维数字模型将扩展蜿蜒通道的过程的知识，超出实验室可实现的量表。