坡面柔性植被阻水效应及其局部水头损失特性试验研究

基于系列坡面流试验,研究了柔性植被条件对坡面流水动力特性的影响.结果表明:由于植被阻水及水流混掺效应,不同区域的水流阻力产生机理存在着显著差异,在植被尾部和水跃段区域,局部水头损失系数与单宽流量的关系分别表现二次曲线特征及指数衰减趋势.此外,基于本试验的植被条件排列方式,以染色法测试坡面流表面流速,得出坡面流平均流速的修正系数约为α=0.23±0.02.

Experimental Study on the Effects of Flexible Vegetation on Hydraulic Characteristics and Local Head Losses of Overland Flow

The series of overland flow experiments were conducted on flexible vegetative beds with 20 degree slopes,and the hydraulic characteristics of sheeted flows were observed for parameters such as surface velocity,flow depth,and the averaged velocity.The local head losses was also calculated.The results showed that the mechanism of flow resistance presents very obvious differences because of the effects of hydraulic jump and aeration on the overland flow around flexible vegetation.The fitting relations showed an exponential function and curve of the second degree,respectively.In addition,the surface flow velocity was made by means of dye-color method,the relationship between surface velocity and averaged velocity was discussed,and the revised coefficient of 0.23 with the distributions of flexible vegetation was obtained.