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通过不同坡度、不同流量的组合放水冲刷试验 ,对坡面细沟侵蚀发生过程中的坡面流水动力学特性进行了研究。结果表明 ,在试验的坡度和流量范围内 ,坡面流的雷诺数变化于 36 2～ 4 2 84之间 ,并且其变化有随冲刷历时和流量的增大而增大的趋势。而坡面流弗劳德数在整个试验过程中均大于 1,属于急流范围。坡面流阻力系数的大小与水流雷诺数有关 ,但其变化趋势受坡度的影响。在坡度较缓时 ,阻力系数随雷诺数的增大而减小 ;在坡度较大时 ,阻力系数随雷诺数的增大而增大。在径流冲刷侵蚀过程中 ,径流流速并非一恒定值 ,而是随冲刷时间的延长和坡面冲刷形态的变化呈现出先减小后稍增大的趋势。
Through the combination of different slopes and different discharges, the runoff scouring test was carried out to study the dynamic characteristics of slope flow in the course of rill erosion. The results show that the Reynolds number of slope flows varies from 362 to 4284 in the slope and flow range of the test, and the change tends to increase with the increase of erosion duration and flow rate. On the other hand, the Froude number of slope flow was greater than 1 during the whole experiment, belonging to the rapids area. The magnitude of slope flow resistance coefficient is related to the Reynolds number of water flow, but the change trend is affected by the slope. When the slope is slow, the drag coefficient decreases with the Reynolds number increasing. When the gradient is larger, the drag coefficient increases with the Reynolds number. During the process of runoff erosion and erosion, the runoff velocity is not a constant value, but tends to decrease slightly and then increase slightly with the extension of erosion time and the change of slope erosion pattern.