摘要
为研究复合坡面径流运动过程及其水力学特性,通过实验室土槽模拟试验,测试了7个径流量（10,15,20,25,30,35,40L/（min·m））和25个坡度（5°~25°）组合（5个直面坡、10个凸型坡和10个凹型坡）条件下的径流流速,计算了径流深度、雷诺数和弗劳德数。结果显示,直面坡径流流速随流程增加而增大并趋于稳定,且随流量或坡度增大而增大。凸型坡下坡面的径流流速大于上坡面,而凹型坡下坡面的径流流速小于上坡面。径流深度的变化规律与流速相反。径流雷诺数沿流程为一常数,而径流弗劳德数则随之增大。径流雷诺数和弗劳德数随径流量增加而显著增大。坡度对雷诺数影响较小而对弗劳德数影响显著。试验条件下,径流雷诺数介于200~800之间,弗劳德数小于2.5。当径流量小于25L/（min·m）时坡面径流属于层流状态,反之为紊流。凸型坡上坡面的径流为缓流而下坡面为急流,凹型坡径流大多数情况下属于急流状态。
In order to study runoff movement process and its hydraulic characteristics on composite slopes,runoff velocity was measured for 7runoff rates（10,15,20,25,30,35,40L/（min·m））and 25combinations（5uniform linear slopes,10 concave slopes,and 10 convex slopes）of slope gradients（5°,10°,15°,20°and 25°）by a series of simulated soil flume experiments in laboratory,and corresponding runoff depth,Reynolds number,and Froude number were calculated as well.Total experimental treatments were 175.Results indicated that runoff velocity on uniform linear slope increased with flow path and progressively tended to be steady,and it increased with the slope gradient or runoff rate.Runoff velocity on the downslope segment of convex slope was greater than that on the upslope segment,while the runoff velocity on the downslope of concave slope was smaller than that on the upslope segment.Runoff depth on uniform linear slope decreased with flow path and tended to be steady,and it increased with the runoff rate or decreased with slope gradient.Runoff depth on the downslope segment of convex slope was smaller than that on the upslope segment,but an opposite tendency existed for concave slope.The Reynolds number（Re）of runoff was a constant value along with flow path,and it increased significantly with the increase of runoff rate but was less affected by slope gradient and the combination of slope gradients.The Froude number（Fr）of runoff increased with flow path,and it increased significantly with the increase of slope gradient or runoff rate.Under experimental conditions,Re value was ranged between 200~800,and Fr value was smaller than 2.5.Runoff belonged to laminar flow when runoff rate was smaller than 25L/（min·m）,otherwise it was turbulent flow.The runoff on upslope segment of convex slope was subcritical flow while that on its downslope segment was torrent flow,and the runoff on concave slope usually belonged to torrent flow status in most cases.
出处
《水土保持学报》
CSCD
北大核心
2016年第5期11-17,共7页
Journal of Soil and Water Conservation
基金
高等学校博士学科点专项科研基金(20120008110024)
国家自然科学基金重点项目(41230746)
关键词
坡型
径流流速
径流深度
水流运动型态
水流流态
slope type
runoff velocity
runoff depth
water flow movement patterns
flow regime
