授予日期
2019年夏天
文档类型
开放获取论文
部门
土木与环境工程
第一个顾问
艾瑞卡Viparelli
摘要
采用示踪颗粒研究了砾石层河流的床质运移。使用它们的优点之一是可以直接测量床载运移和颗粒位移中的颗粒夹带率。示踪剂颗粒现场研究的主要问题是示踪剂短期和长期行为之间的差异。这种差异是由于粒子进行垂直混合或移动到较不活跃的位置，如酒吧或甚至泛滥平原。由于这些原因，平均示踪剂速度随着时间的推移而降低。这种现象被称为示踪剂减速，它对估算床层运移或模拟污染砂砾的扩散具有重大影响。绝大多数解释床层材料(示踪剂和非示踪剂)非均匀性的形态动力学模型都是基于冲积沉积物的离散描述。矿床分为两个不同的区域;活性层和衬底。活动层是沉积物最上层的一层薄层，其中颗粒可以与床层物质相互作用。 The substrate is the part of the deposit below the active layer. Due to the discrete representation of the alluvial deposit, active layer models are not able to reproduce tracer slowdown. To overcome some of the limitations of layer-based models, Parker and co-authors introduced probabilistic, not layer-based morphodynamic framework. This framework is based on a probabilistic description of the temporal variation of bed surface elevation associated with sediment transport processes, and it is used herein to model the dispersal of tracer particles. Particle entrainment rates are computed as a function of the flow and sediment characteristics, and particle deposition is modeled with a step length formulation. Here we present one of the first implementation of the probabilistic framework at laboratory scale, validate it against laboratory data, and then we use the validated model to investigate some of the characteristics of tracer dispersal at laboratory and field scales.
建议引用
Borhani,美国(2019年)。在床上荷载主导环境下的粒子扩散建模。(博士论文)。检索自https://scholarcommons.www.eternity-eta.com/etd/5372