COLLABORATIVE RESEARCH: The statistical mechanics of bed load sediment transport: Scaling particle motion to fluvial form

合作研究：床载沉积物输送的统计力学：将颗粒运动缩放为河流形式

基本信息

批准号：
1734752
负责人：
Mark Schmeeckle
金额：
$ 45.52万
依托单位：
Arizona State University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2022-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1734752&HistoricalAwards=false
关键词：
COLLABORATIVE RESEARCH statistical mechanics bed

项目摘要

The streams and rivers of the United States are in a state of flux due to the building, and now decommissioning, of tens of thousands of dams, as well as changes in water use and land use influencing river flows. Extensive field studies have documented complex changes to the geometry and substrate of gravel-bedded rivers affecting fish and other biota. Due to the patchy, intermittent nature of the motion of sand and gravel carried by turbulent river flow, current models of sediment transport are unable to predict most of these critical riparian changes. This project investigates and describes sediment motion at the level of individual grains and turbulent eddies using physics-based supercomputer algorithms and advanced laboratory imaging techniques. Statistical physical principles are applied to these supercomputer and laboratory results to produce a theoretical framework that is expected to provide predictive capabilities, and thus, policy guidance regarding dramatic changes occurring in the country's waterways.The experimental work involves gravel-bed flumes and high-speed video to illustrate the basis for changes in streambed topography, and how the characteristic length-scales in this problem are determined by the distribution of particle motions. Laboratory experiments will be replicated by particle- and turbulence-resolving supercomputer simulations coupled in momentum. The work also is aimed at parameterizing statistical theory for the case of alternate bar formation, thus providing the basis for further clarifying channel-scale morphodynamics problems in which patchy, rarefied transport conditions exist.This award is cofunded by the Geomorphology and Land-use Dynamics Program and the National Strategic Computing Initiative.

由于数以万计的水坝的修建和现已退役，以及影响河流流量的用水和土地利用的变化，美国的溪流和河流处于不断变化的状态。广泛的实地研究记录了砾石层河流的几何形状和基质的复杂变化影响鱼类和其他生物群。由于湍流河流携带的沙子和砾石的运动具有不连续性和间歇性，当前的沉积物输送模型无法预测大部分关键的河岸变化。该项目使用基于物理的超级计算机算法和先进的实验室成像技术来研究和描述单个颗粒和湍流涡旋水平的沉积物运动。统计物理原理应用于这些超级计算机和实验室结果，以产生一个理论框架，有望提供预测能力，从而为该国水道发生的巨大变化提供政策指导。实验工作涉及砾石床水槽和高速视频说明了河床地形变化的基础，以及该问题中的特征长度尺度是如何由粒子运动的分布决定的。实验室实验将通过动量耦合的粒子和湍流解析超级计算机模拟来复制。这项工作的目的还在于对交替坝形成情况的统计理论进行参数化，从而为进一步阐明存在斑块、稀薄输运条件的河道尺度形态动力学问题提供基础。该奖项由地貌学和土地利用动力学共同资助计划和国家战略计算计划。