摘要
为深入揭示植被覆盖条件下坡面水流结构的内在规律,采用水槽模拟试验,系统研究了植被处于淹没及非淹没工况下淹没度对坡面流水动力学特性的影响。研究结果表明:坡度一定条件下,平均流速和雷诺数与淹没度均成正相关关系;柔性植被覆盖下,水流流型由缓流区过渡到急流区,综合阻力系数随淹没度的增加而减小,刚性植被覆盖条件下水流流型均处于缓流区;综合阻力系数呈单驼峰形式变化;峰值处淹没度为0.9,淹没度对相对摩阻流速的影响与其对阻力系数呈相反变化趋势,基于淹没度的阻力计算经验公式决定系数均达到0.97以上;由于淹没度对各水动力学参数的影响受制于坡度,在坡面水土保持中应根据山区坡度和水深选择适当的植被高度。
In order to explore the inherent law of slope flow structures under vegetation, we systematically re- searched, by testing via artificial vegetation simulation, the influence of submergence on the kinetic characteristics of slope flow in conditions where the vegetation is submerged or unsubmerged. According to the research： given the same gradient, both the average flow velocity and Reynolds number have a positive correlation with the degree of submer- gence ; under flexible vegetation, slope flow changes from slow to rapid as the degree of submergence increases, the o- verall resistance coefficient drops with the increase of submergence degree ; while under rigid vegetation, slope flow al- ways remains slow, the overall resistance coefficient varies in a curve like single hump, the degree of submergence is 0. 9 when the resistance coefficient peaks. The influence of submergence on the relative friction velocity is opposite to that on the resistance coefficient, the coefficient of determination of an empirical equation for calculating the resistance can be more than 0.97 based on the degree of submergence; the influence of submergence degree on hydrodynamic parameters is dependent on the slope gradient, so for conservation of soil and water on slopes, appropriate vegetation heights should be determined according to the slope and water depth of hilly regions.
作者
杨帆
张宽地
杨明义
杨婕
YANG Fan ZHANG Kuandi YANG Mingyi YANG Jie(College of Water Resources and Architectural Engineering, Northwest A＆F University, Yangling 712100, China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, CAS ＆ MWR, Yangling 712100, China)
出处
《水科学进展》
EI
CAS
CSCD
北大核心
2016年第6期832-840,共9页
Advances in Water Science
基金
国家自然科学基金资助项目(51209222
41001159)~~
关键词
植被覆盖
淹没度
相对摩阻流速
阻力系数
水动力学特性
坡面流
vegetation coverage
submergence degree
relative shear velocity
resistance coefficient
hydrauliccharacteristic
slope flow
