COLLABORATIVE RESEARCH: Experimental Study of the Effect ofSediment Sorting on Bed Forms, Bed-Surface Texture, and Fractional Transport Rates in Coarse Mixed-Size Sediments

合作研究：沉积物分选对粗粒混合粒度沉积物的床形态、床表面结构和分数输送率影响的实验研究

• 批准号: 9017937
• 负责人: Peter Wilcock
• 金额: $ 2.03万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-04-01 至 1994-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9017937&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Experimental; Study; Effect

When a unidirectional current passes over a bed of coarse mixed-size sediment, a variety of bed forms are generated and there is a segregation of particle sizes among the load, the bed surface layer and the substrate. There is a strong and complex interdependence between the bed forms, the transported sediment and the substrate. Many studies in well sorted sands, both in the laboratory and in the field, have led to fairly good understanding of the behavior of the familiar dune bed forms and the interaction between bed forms and transport. More recently, features variously described as bed-load sheets, gravel waves, and clast jams have been reported in flows over poorly sorted sand-gravel mixtures. The relationships among these seemingly diverse bed features, and their dependence on size segretation in the bed, is unclear. This is an experimental study of the nature of bed features in unidirectional flows as a function of flow strength and sediment sorting involving several sediment mixtures with the same mean size of about 4mm but with widely varying sorting and making series of runs at several mean flow velocities over each sediment mixture. The objective is a unified picture of the fundamental characteristics and interrelationships of the various kinds of bed features produced in these flows. The work will be done in cooperation with Prof. Hiroshi Ikeda, Prof. Shigemi Takayama, and Dr. Fujiko Iseya of the Environmental Research center at the University of Tsukuba. This proposal covers salary and travel for the PI. A companion proposal with identical scientific text is being submitted by Prof. John B. Southard (MIT). The Japanese group already has funds for building the experimental apparatus and conducting the experiments.

当一股单向水流流过粗砂层时 混合大小的沉积物，各种床的形式产生， 在装载物、床层 表面层和基底。 有一种强烈而复杂的 河床形态、输沙量、 和衬底。 许多研究在良好分选的砂，无论是在 在实验室和现场，已经导致了相当好的 了解熟悉的沙丘床形态的行为， 河床形态和运输之间的相互作用。 最近， 各种各样的特征被描述为推移质层，砾石波， 据报道，碎屑堵塞的情况发生在分选不良的河流上， 砂砾混合物 这些看起来 不同的床特征，以及它们对粒度分离的依赖性， 床，不清楚。 这是一项关于河床特征性质的实验研究 在单向流动中，作为流动强度的函数， 沉积物分选涉及几种沉积物混合物， 平均尺寸相同，约为4 mm，但分选差异很大， 以几个平均流速在每个 沉积物混合物 目标是统一描述 基本特点和相互关系的各种 在这些流动中产生的各种床特征。 这项工作将与Hiroshi教授合作完成 池田教授、高山茂美教授和 筑波大学环境研究中心。 这 建议书包括PI的工资和差旅费。 一个同伴 以下国家提交了具有相同科学文本的提案： John B教授。Southard（MIT）. 日本集团已经在 建立实验装置和进行 实验