Exploring turbulence-sediment dynamics for river erosion control

探索河流侵蚀控制的湍流-泥沙动力学

• 批准号: RGPIN-2020-06796
• 负责人: Li, SSamuel
• 金额: $ 2.26万
• 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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=746391
• 关键词: Exploring; turbulence; sediment; dynamics; river

The applicant proposes to study turbulence and its interaction with sediments in water channels. Turbulence over channel-beds causes bed-sediment scour and deposition, influencing the stability of a river channel. Channel instability has a detrimental impact on the effectiveness of river engineering schemes for flood control, navigation improvement, and the safe use of in-stream structures. The flow dynamics of the sediment-water interface region are complex and poorly understood. The objective of the proposed research is to provide an improved understanding of complex flow dynamics. In a river confluence, two streams of different flow velocities combine to form a single channel, the combining flow features velocity shear. The associated vorticity can lead to hydrodynamic instability and the development of turbulence. Turbulent eddies have the ability to scour sediment particles from the bed and sweep them downstream. Past research has focused on turbulent mixing between the incoming fluids, assuming negligible bed friction. This assumption is invalid for flows through a shallow confluence. The applicant intends to investigate the role of shallowness in the interaction between fluid- and sediment-particles by means of laboratory measurements and particle trajectory simulations. The simulations will consider both open-water and ice-covered conditions. The results will be useful for the development of effective strategies for the protection of confluence stability and benthic ecology. In a channel expansion, water flow typically separates from one or both of its sidewalls. Flow separation creates turbulent eddies of various sizes. Larger eddies bear more energy and are capable of interacting with sediment particles. The result is scour, deposition, and bed evolution within the expansion and often further downstream. The applicant plans to conduct laboratory experiments and morphodynamic simulations in order to find solutions to the problem of scour in channel expansions. The applicant will use advanced measurement techniques (laser Doppler anemometry and three-dimensional particle tracking velocimetry) to produce reliable measurements of the instantaneous flow velocity and particle trajectories. Digital positioning devices will allow accurate and repeatable measurements. The applicant will perform particle tracking simulations and high-resolution sediment scour simulations on high performance computing clusters. The laboratory measurements and the mathematical predictions are complementary to each other. In Canada, turbulence-induced erosion is omnipresent in rivers, streams, drainage canals, and water supply channels. The results from this proposed research will help achieve two long-term objectives: (a) developing sound analysis and prediction strategies to support practical and managerial activities in river engineering and water resources engineering; (b) creating reliable data for decision makers to address environmental and economic needs.

申请人建议研究湍流及其与水通道中沉积物的相互作用。通道床上的湍流会导致床位的冲刷和沉积，从而影响河道的稳定性。通道不稳定性对河流工程计划对防洪，导航改善以及安全使用式河流结构的有效性有害。沉积物 - 水界面区域的流动动力学很复杂且了解不足。拟议的研究的目的是提供对复杂流动动力学的改进理解。在河流汇合处，两个不同流速度的流相结合形成一个单个通道，结合流动速度剪切。相关的涡度可以导致流体动力不稳定和湍流的发展。湍流的涡流具有从床上搜集沉积物颗粒并将其扫到下游的能力。过去的研究集中在传入的液体之间的湍流混合，假设床摩擦可忽略不计。对于通过浅汇合的流量，此假设是无效的。申请人打算通过实验室测量和粒子轨迹模拟来研究浅层植物在流体和沉积物之间相互作用中的作用。模拟将考虑开放水和冰覆盖的条件。结果将对制定有效的融合稳定性和底栖生态的策略有用。在通道膨胀中，水流通常与其一个或两个侧壁分离。流动分离会产生各种大小的湍流涡流。较大的涡流具有更多的能量，并且能够与沉积物颗粒相互作用。结果是在膨胀内，通常在下游进一步的冲刷，沉积和床的演变。申请人计划进行实验室实验和形态动力学模拟，以找到解决通道扩展中冲刷问题的解决方案。申请人将使用先进的测量技术（激光多普勒动态测定法和三维粒子跟踪速度计）来生成瞬时流速和粒子轨迹的可靠测量。数字定位设备将允许准确且可重复的测量。申请人将对高性能计算簇进行粒子跟踪模拟和高分辨率沉积物仿真模拟。实验室测量和数学预测是彼此互补的。在加拿大，湍流引起的侵蚀在河流，溪流，排水管和供水通道中无处不在。这项拟议的研究的结果将有助于实现两个长期目标：（a）制定声音分析和预测策略，以支持河流工程和水资源工程中的实践和管理活动； （b）为决策者创建可靠的数据，以满足环境和经济需求。