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Estimating flow resistance in steep slope rills
Hydrological Processes ( IF 2.8 ) Pub Date : 2021-06-30 , DOI: 10.1002/hyp.14296
C. Di Stefano 1 , A. Nicosia 1 , V. Palmeri 1 , V. Pampalone 1 , V. Ferro 2
Affiliation  

Recent research recognized that the slope of 18% can be used to distinguish between the ‘gentle slope’ case and that of ‘steep slope’ for the detected differences in hydraulic variables (flow depth, velocity, Reynolds number, Froude number) and those representatives of sediment transport (flow transport capacity, actual sediment load). In this paper, using previous measurements carried out in mobile bed rills and flume experiments characterized by steep slopes (i.e., slope greater than or equal to 18%), a theoretical rill flow resistance equation to estimate the Darcy-Weisbach friction factor is tested. The main aim is to deduce a relationship between the velocity profile parameter Γ, the channel slope, the Reynolds number, the Froude number and the textural classes using a data base characterized by a wide range of hydraulic conditions, plot or flume slope (18%–84%) and textural classes (clay ranging from 3% to 71%). The obtained relationship is also tested using 47 experimental runs carried out in the present investigation with mobile bed rills incised in a 18%—sloping plot with a clay loam soil and literature data. The analysis demonstrated that: (1) the soil texture affects the estimate of the Γ parameter and the theoretical flow resistance law (Equation 25), (2) the proposed Equation (25) fits well the independent measurements of the testing data base, (3) the estimate of the Darcy-Weisbach friction factor is affected by the soil particle detachability and transportability and (4) the Darcy-Weisbach friction factor is linearly related to the rill slope.

中文翻译:

估计陡坡细沟中的流动阻力

最近的研究认识到,对于检测到的水力变量(水流深度、速度、雷诺数、弗劳德数)和那些代表的差异,18% 的斜率可用于区分“缓坡”情况和“陡坡”情况输沙量(水流输送能力、实际泥沙负荷)。在本文中,利用以前在具有陡坡(即坡度大于或等于 18%)的移动式底细沟和水槽实验中进行的测量,测试了用于估计 Darcy-Weisbach 摩擦系数的理论细沟流阻力方程。主要目的是使用以各种水力条件为特征的数据库推导出速度剖面参数 Γ、通道斜率、雷诺数、弗劳德数和纹理类别之间的关系,地块或水槽斜率 (18%–84%) 和质地类别(粘土范围从 3% 到 71%)。获得的关系还使用在本调查中进行的 47 次实验运行进行了测试,其中移动床细沟切入 18% 的坡地,粘壤土和文献数据。分析表明:(1)土壤质地影响Γ参数的估计和理论流阻定律(方程25),(2)所提出的方程(25)与测试数据库的独立测量值吻合,( 3) Darcy-Weisbach 摩擦系数的估计值受土壤颗粒可分离性和可迁移性的影响,(4) Darcy-Weisbach 摩擦系数与细沟坡度线性相关。获得的关系还使用在本调查中进行的 47 次实验运行进行了测试,其中移动床细沟切入 18% 的坡地,粘壤土和文献数据。分析表明:(1)土壤质地影响Γ参数的估计和理论流阻定律(方程25),(2)所提出的方程(25)与测试数据库的独立测量值吻合,( 3) Darcy-Weisbach 摩擦系数的估计值受土壤颗粒可分离性和可迁移性的影响,(4) Darcy-Weisbach 摩擦系数与细沟坡度线性相关。获得的关系还使用在本调查中进行的 47 次实验运行进行了测试,其中移动床细沟切入 18% 的坡地,粘壤土和文献数据。分析表明:(1)土壤质地影响Γ参数的估计和理论流阻定律(方程25),(2)所提出的方程(25)与测试数据库的独立测量值吻合,( 3) Darcy-Weisbach 摩擦系数的估计值受土壤颗粒可分离性和可迁移性的影响,(4) Darcy-Weisbach 摩擦系数与细沟坡度线性相关。
更新日期:2021-07-21
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