牛轭湖出口段淤积过程的数值模拟  

Numerical modeling of deposition process at outlet of an oxbow lake in the upper Black River of the Yellow River Source

作　　者：李想 李志威[1,3] 胡旭跃 LI Xiang;LI Zhi-wei;HU Xu-yue(School of Hydraulic Engineering,Changsha University of Science&Technology,Changsha 410114,China;Hunan Hydro&Power Design Institute,Changsha 410007,China;Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province,Changsha 410114,China)

机构地区：[1]长沙理工大学水利工程学院,湖南长沙410114 [2]湖南省水利水电勘测设计研究总院,湖南长沙410007 [3]水沙科学与水灾害防治湖南省重点实验室,湖南长沙410114

出　　处：《泥沙研究》2020年第4期52-58,共7页Journal of Sediment Research

基　　金：国家自然科学基金项目(51709020,51979012);湖南省教育厅重点项目(19A017);湖南省自然科学基金项目(2020JJ3036);湖南省水电院青创项目(QC201813)。

摘　　要：牛轭湖出口段主要以悬移质淤积为主,其沙栓淤积过程尚缺少研究。结合黄河源黑河支流麦曲的观测数据,采用MIKE3模拟牛轭湖出口段沙栓的淤积过程。牛轭湖出口段淤积分为进口漫水与回流淤积两个阶段,前者仅在出口段的底部少量淤积,后者在横向环流作用下悬移质在出口段发生累积性淤积。牛轭湖出口段淤积的主要因素是悬移质中值粒径、上游来流量和悬沙浓度。来流量越大,引起出口段横向环流中心的紊动强度增大,从而促进泥沙悬浮,导致出口段两岸边滩更易淤积。悬移质浓度的增加会同时抑制出口段底层泥沙起动,促进沙栓的形成与淤高。The outlet of an oxbow lake is mainly subjected to suspended load deposition,but the sand plug processes are still an important topic to study. Using MIKE3 module,combined with the field measurements of Maiqu River of the upper Black River of the Yellow River Source Zone,a numerical model for sand plug formation at the outlet section of an oxbow lake was established to simulate the deposition process,which is divided into two stages,i.e.,overbank flow at the outlet and backflow deposition. The former has only a small amount of deposition at the bottom,while the latter is the cumulative deposition at the outlet under the influence of lateral circulation. The main factors for sediment deposition at the outlet are sediment median size,incoming flow discharge,and suspended load concentration. The larger incoming discharge,the greater the turbulence intensity in the lateral circulation center at the outlet section. The higher suspended load concentration results in more deposition on both sides at the outlet section. Moreover,the increase of suspended load concentration may inhibit the sediment incipient at the bottom of the outlet section,and further accelerate the formation of sand plug.

关 键 词：弯曲河流 牛轭湖 悬移质淤积 横向环流 数值模拟 黄河源 

分 类 号：TV147[水利工程—水力学及河流动力学]