黄土坡面细沟水流佛汝德数试验研究

Experimental Study of Rill Flow State on Loess Hillslope

采用组合小区模拟降雨试验方法,对黄土坡面细沟水流水力学特性佛汝德数（Fr）进行试验研究。结果表明：1细沟水流流态判别指标Fr随径流历时的变化,在不同雨强及坡度下皆表现为减小趋势,皆可用指数方程描述;2细沟水流平均Fr随雨强及坡度的增大而增大,可分别用幂函数方程和指数方程描述,随雨强、坡度的变化可用二元指数方程描述;3在不同雨强及坡度下,一次降雨径流过程的细沟水流平均Fr变化于6.309~7.336之间,表明坡面细沟水流流态属于急流。

The slope flow state in rill erosion process on loess hillslope were studied by a multi-plot experiments under simulated rainfall, The results showed that： 1） the rill flow Froude number（Fr）, a judging index of flow state, decreased with rainfall intensity and slope. The exponential equation could describe the trend. 2） The average Fr of rill flow increased with increasing rainfall intensity or slope, which could be described by the power function equation and exponential equation respectively, while could be described by a dual exponential equation to both factors. 3） The average Fr varied between 6.309 and 7.336, indicating that rill flow was rapid.