Fluvial Processes and River Dynamics

河流过程和河流动力学

• 批准号: 2657-2013
• 负责人: Roy, André
• 金额: $ 2.91万
• 依托单位: Concordia University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=592723
• 关键词: Fluvial; Processes; River; Dynamics

Alluvial rivers are complex and fundamental components of the natural environment and a key resource for human activities and for wildlife. Although rivers have been extensively studied in the past, their dynamics and response to environmental changes, both natural and anthropogenic, are still far from being understood. Numerous spectacular examples of major and unforeseen impacts on the shape, size and pattern of alluvial channels have been caused by severe floods or by periods of drought such as those recently witnessed in North America and elsewhere. In order to understand the behaviour of rivers we need to advance our knowledge on the fundamental mechanical processes that drive the fluvial system. This research program focuses on the relationships, feedbacks and mutual adjustments between flow structure, sediment mobility and the resulting adjustments of the bed (form and bed material distribution) in rivers. The particular scope of the research is on the role of flow turbulence (i.e. smaller scales of motion in fluid flow) in these relationships. The long-term objective of the research program is to integrate turbulence within the larger scale behaviour (time and space) of rivers. The specific objectives of the research program are to: 1) test the generality of the properties, origin and evolution of macroturbulent flow structures and flow pulsations; 2) quantify the role of flow turbulence as it interacts with other large scale flow motions (e.g. pulsations, secondary currents); 3) link the properties and dynamics of sediment transport episodes/events to the turbulent/pulsations flow structures in gravel-bed rivers and 4) quantify the effects and feedbacks of flow unsteadiness and non-uniformity on sediment transport and morphological changes as flow stage changes. These objectives will be met through interconnected projects that will rely on both classical and innovative methods and in situ experimental designs. The experiments will be conducted at a selection of field sites in southern Québec and Ontario, one of which has permanent installations for the high resolution measurements of flow, bed topography and particle displacements. Laboratory experiments will complement the work on natural rivers.

冲积河是自然环境的复杂和基本组成部分，也是人类活动和野生动植物的关键资源。尽管过去的河流已经广泛研究，但它们对自然和人为变化的动态和对环境变化的反应仍然远非被理解。许多壮观的例子是对冲积渠道的形状，大小和模式产生的重大和不可预见的影响是由严重地板或干旱时期引起的，例如最近在北美和其他地方见证的那些。为了了解河流的行为，我们需要促进有关驱动河流系统的基本机械过程的知识。该研究计划的重点是河流中床（形式和床材料分布）的流动结构，沉积物移动性和由此产生的调整之间的关系，反馈和相互调整。该研究的特殊范围在于这些关系中流动湍流（即运动流动流中较小的运动尺度）的作用。研究计划的长期目标是将湍流纳入河流的较大规模行为（时间和空间）。研究计划的特定目标是：1）测试大型流动结构和流动脉动的性质，起源和演变的一般性； 2）量化流动湍流与其他大规模流动运动相互作用（例如脉动，次级电流）时的作用； 3）将沉积物传输发作/事件的性质和动态与毕业床中的湍流/脉动流量结构联系起来，4）量化流动不稳定和不均匀性的影响和反馈对沉积物传输和形态变化的影响和反馈，因为流动阶段变化。这些目标将通过相互联系的项目来实现，这些项目将依靠经典和创新方法以及原位实验设计。实验将在魁北克省南部和安大略省南部的野外现场进行选择，其中一个具有永久性安装，用于高分辨率测量，床地图和粒子位移。实验室实验将完成关于天然河流的工作。