河宽缩窄率对河床冲刷形态影响数值模拟研究  

Numerical simulations of the impacts of river width narrowing ratio on riverbed deformation

作　　者：宁健[1] 李国栋[1] 马淼[1] 

机构地区：[1]西安理工大学西北旱区生态水利工程国家重点实验室培育基地,西安710048

出　　处：《水力发电学报》2017年第8期43-49,共7页Journal of Hydroelectric Engineering

基　　金：国家自然科学基金(51579206);陕西省自然科学基础研究计划(2015JM5201)

摘　　要：丁坝的存在导致河道流场结构发生变化,进而引起丁坝坝头的局部冲刷,并对附近的河床演变产生影响,河宽缩窄率(丁坝长度与河宽比值)是影响河道局部冲刷形态的重要参数。本文采用数值模拟方法研究不同河宽缩窄率情况下,非淹没丁坝坝头冲刷深度及冲刷形态的变化规律。结果表明,河宽缩窄率0.5以下时,最大冲刷深度随河宽缩窄率的增加基本上呈线性增加,河宽缩窄率超过0.5以后,最大冲刷深度增加剧烈,同时丁坝对水流的影响范围也达到了对岸,冲坑的范围扩展到了河对岸边,且冲坑形态也发生了较大的变化。研究成果对于实际丁坝工程选择适当的河宽缩窄率具有重要的参考借鉴意义。Spur dikes lead to a change in the flow structure and have an impact on the local scour around its head and the evolution of riverbed nearby. River width narrowing ratio （i.e. the ratio of spur dike length to river width） is a key factor of its local scour features. Based on numerical simulations of the 3D flows, this paper analyzes the scour depth and riverbed deformation around the head of a non-submerged spur dike at different narrowing ratios. Results reveal that the maximum scour depth essentially linearly increases with the narrowing ratio in its range of 0.5 or less but it increases more rapidly at the ratio beyond this range. In the latter case, the scope of a spur dike on the flow reaches the opposite bank, and consequently the scour pit also extends to the shore, taking a shape greatly different from those at the smaller ratios. This indicates the significance in selecting a suitable river width narrowing ratio in design of practical spur dikes

关 键 词：非淹没丁坝 数值模拟 河宽缩窄率 最大冲刷深度 

分 类 号：TV147[水利工程—水力学及河流动力学]