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.

冲积河流是自然环境的复杂而基本的组成部分，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，但它们的动态以及对自然和人为环境变化的响应仍远未得到研究。为了了解河流的行为，严重的洪水或干旱时期（例如最近在北美和其他地方发生的干旱）对冲积河道的形状、大小和格局造成了许多重大和不可预见的影响。我们需要增进我们对驱动河流系统的基本机械过程的了解，该研究项目重点关注河流中水流结构、沉积物流动性以及由此产生的河床调整（形式和河床物质分布）之间的关系、反馈和相互调整。研究范围是流动湍流（即流体流动中较小尺度的运动）在这些关系中的作用。该研究计划的长期目标是将湍流整合到河流的较大尺度行为（时间和空间）中。 。该研究计划的具体目标是：1）测试宏观湍流结构和流动脉动的特性、起源和演变的普遍性；2）量化流动湍流与其他大规模流动运动（例如脉动、 3) 将沉积物输送事件/事件的特性和动态与砾石河床河流中的湍流/脉动流结构联系起来，4) 量化影响和随着流动阶段的变化，流动不稳定和不均匀性对沉积物迁移和形态变化的反馈将通过依赖经典和创新方法以及现场实验设计的相互关联的项目来实现。魁北克省南部和安大略省的多个现场站点，其中一个拥有用于流量、河床地形和颗粒位移的高分辨率测量的永久性装置，实验室实验将补充天然河流的工作。