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物的重要资源。尽管过去对河流进行了广泛的研究，但对河流的动态及其对自然和人为环境变化的响应仍然知之甚少。对冲积河道的形状、大小和格局造成重大和不可预见的影响的许多惊人例子都是由严重的洪水或像最近在北美和其他地方目睹的干旱时期造成的。为了理解河流的行为，我们需要提高我们对驱动河流系统的基本机械过程的知识。本研究项目主要研究河流水流结构、泥沙流动及其对河床（形态和河床物质分布）的调节之间的关系、反馈和相互调节。研究的特定范围是流动湍流（即流体流动中较小尺度的运动）在这些关系中的作用。研究计划的长期目标是将湍流整合到河流的更大尺度行为（时间和空间）中。该研究项目的具体目标是：1)测试宏观湍流结构和流动脉动的性质、起源和演变的普遍性；2)量化湍流与其他大尺度流动运动（如脉动、二次流）相互作用时的作用；3)将输沙事件的性质和动力学与砾石河床湍流/脉动流结构联系起来；4)量化水流阶段变化时，水流不稳定和不均匀性对输沙和形态变化的影响和反馈。这些目标将通过相互关联的项目来实现，这些项目将依靠经典和创新的方法以及原位实验设计。实验将在魁省南部和安大略选定的几个场址进行，其中一个场址有永久性装置，用于高分辨率测量流量、河床地形和颗粒位移。实验室实验将补充对天然河流的研究。