植被排列方式及坡度对坡面流Fr影响的试验研究

Impact of vegetation arrangement and slope gradient on the overland flow Froude number

为探究植被的排列方式及坡度大小对坡面流弗劳德数Fr的影响,以期揭示坡面流弗劳德数Fr的内在规律。利用人工模拟试验,系统研究了6个坡度、3种植物排列方向与水流方向呈不同走向角的条件下Fr与单位底面积的空间摩阻表面积K值的特征关系。表明在非淹没状态下,Fr与K值的关系为随K值的增大Fr呈现先减小后趋于平稳的趋势;Fr的取值随坡度的增大而增大;在一定的坡度范围内,同一坡度下,当Fr>1时,同一K值下,走向角越大对应的Fr值越小,当Fr<1时则相反;同一走向角下,在同一K值下,坡度越大对应的Fr就越大。得出在坡度一定的条件下,坡面植被的排列方式不同,弗劳德数Fr的取值也不相同;坡度是影响Fr取值范围的重要因素之一。

[Objective]To explore the impact of vegetation arrangement and slope gradient on the over land flow Froude number Fr,in order to reveal the inherent law of over land flow Froude number Fr.[Method]Using artificial simulation tests,we systematically studiedthe relationship between Fr and Kvalue,which is the friction surface area of a unit floor area,under different conditions including sixslo peg radients and three angles between the vegetation arrangement direction and water flow direction.[Results]In non-submerg edflow,with the increase of K,Fr would decrease first and then tend to be steady,and the value of Fr would increase with the increase ofslopeg radient.Within a certain rang e of slope gradient,with the same gradient,when Fr>1,with the same Kvalue,the bigger the direction angle,the smaller the Fr.when Fr<1,the situation was the other way around.With the same angle and the same K,the greaterthe gradient,the greater the cor responding Fr.[Conclusion]At a certain g radient,when the slope veg etation arrangement varies,theFroude number Fr value varies as well.The slope gradient is one of the important factors that influence Fr value range.