为深入研究植被减流减沙特征及对流域水土保持效益的影响,本文通过5个覆盖度,6个坡度和7个流量的组合条件下的室内放水试验,系统研究了植被对坡面水流的缓流特征。结果表明:随着植被覆盖度增加,植被对坡面水流的阻滞作用逐渐凸显,即缓流系数减小,缓流效果增强,当植被覆盖度大于4.650%时,缓流效果趋于稳定。在试验流量范围内,缓流系数随流量的增加呈现逐渐减少的趋势,而随坡度的增加略有增加。缓流系数随水深和雷诺数增加而减小,而与弗劳德数呈反C型分布。最后,建立了基于试验控制变量(植被覆盖度,流量和坡度)的缓流系数预测公式。
Flow slowing characteristics of vegetation are studied under 6 slopes, 7 flow discharges and 5 vegetation coverages. Results show that influence of flow slowing coefficient decreases, and flow slowing effects are enhanced, when vegetation coverage is more than 4. 650% , flow slowing effects tend to stable; it decreases with the increases of the flow, but increases while slope increases. The flow slowing coefficient decreases with the depth and the Reynolds number increasing, however, it negatively correlates with the Froude Number, with positively correlation relationships. Based on control variables of the experiment (vegetation coverage, flow discharge and slope) , the equation of current slowing coefficient is set up.