Analytical model for stage-discharge estimation in meandering compound channels with submerged flexible vegetation
Analytical model for stage-discharge estimation in meandering compound channels with submerged flexible vegetation
复制标题
水下柔性植被蜿蜒复合河道阶段流量估算分析模型
DOI：
10.1016/j.advwatres.2017.07.021
复制
发表时间：
2017
影响因子：
4.7
通讯作者：
Liu Chao
中科院分区：
文献类型：
--
作者：
Shan Yuqi;Liu Xingnian;Yang Kejun;Liu Chao
漫滩水流中，漫滩上的沉水柔性植被增加了河道阻力，降低了河道输水能力。本研究提出一个分析模式，以评估高流量条件下，在一个曲折的复式河道与密集，淹没，灵活的植被漫滩的水位流量关系。将林冠内的平均速度与深度平均速度联系起来，提出了两者之间的关系。在曲线坐标系下推导了控制方程，并通过大尺度弯曲河道的实验测量验证了横向剪应力可以忽略不计。在此基础上，在不考虑侧向剪应力的情况下，推导了分区流量和总流量的解析解。两个水槽实验和一个现场研究的测量被用来验证所提出的模型。实地案例涉及一条天然河流，洪泛平原上既有淹没的草，也有涌现的草。预测和测量之间的良好协议表明，该模型准确地预测分区流量和水位流量关系在一个曲折的复合渠道与淹没植被。最后，该模型的预测是敏感的二次流参数在主渠道，但不敏感的漫滩。
For overbank flows, submerged flexible vegetation on floodplains increases channel resistance and decreases channel conveyance capability. This study presents an analytical model for estimating the stage-discharge relationship in a meandering compound channel with dense, submerged, flexible vegetation on floodplains under high flow conditions. The mean velocity within a canopy was linked to the depth-averaged velocity, and a relationship between the two velocities was proposed. The governing equation was deduced in curvilinear coordinates, and the lateral shear stresses were found to be negligible, as validated by our experimental measurements in a large-scale meandering channel. Then, analytical solutions of subarea discharges and total discharge were derived by ignoring lateral shear stresses. Measurements from two flume experiments and one field study were used to verify the proposed model. The field case involved a natural river with both submerged and emergent grass on the floodplains. Good agreement between predictions and measurements indicated that the model accurately predicted subarea discharges and the stage-discharge relationships in a meandering compound channel with submerged vegetation. Finally, the predictions of this model were sensitive to the secondary flow parameters in the main channel but insensitive to those on the floodplains.