植被条件下坡面薄层水流动力学特性试验研究

基于系列坡面流试验,研究了植被条件对坡面流水动力特性的影响。结果表明:相同流量与坡度条件下,由于柔韧植被的阻水作用,光面条件下的流速远大于柔韧植被作用的流速,随着植被刚度及密度的增加,坡面流流速、弗劳德数呈现递减趋势。由于植被阻水及水流混掺效应,Darcy-Weisbath阻力系数基本随雷诺数增大而增大,而一般研究认为阻力系数随雷诺数的增大而减小,由此表明,坡面阻力系数与雷诺数并不存在单调的递增或递减关系,而与坡面糙度单元组成存在较强的依赖关系。

Experimental Study on the Effects of Vegetation on Hydraulic Characteristics of Overland Flow

The series of overland flow experiments were conducted on smooth and vegetative beds with varied slopes, and the hydraulic characteristics of sheeted flows were observed for parameters such as flow velocity, Froude numbers, and resistance coefficient. The results show that the flow velocity and Froude numbers decrease with the increasing of the rigidity and the density of vegetation, and flow velocity will decrease after the discharge increases under gentle slope conditions, and in this case there mainly exists subcritical flow in the flume. The Darcy-Weisbath resistance coefficient increases with the increasing of the rigidity and the density of vegetation because of the effects of vegetation on overland flow while the inverse relationship often exists on different roughness slope.