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首页> 外文期刊>Vadose zone journal VZJ >Flow Resistance in Step-Pool Rills
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Flow Resistance in Step-Pool Rills

机译：阶梯池中的流动性

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Rills evolve morphologically, and the adjustment of rill channel geometry to flow affects the relationships among velocity, discharge, and slope. The resistance to flow in step-pool rills is mainly due to form-induced mechanisms and, in comparison, grain resistance is of minor significance. Previous studies on rill flow resistance have been performed exclusively for grain-resistance conditions and use a stream flow equation. In this study, a new flow resistance equation, deduced by applying dimensional analysis and self-similarity theory, was applied to rill flow in step-pool channels. First, the incomplete self-similarity hypothesis was used for establishing a power flow velocity profile whose integration gives the theoretical expression of the Darcy-Weisbach friction factor. Then the deduced theoretical resistance equation was tested by measurements of flow velocity, water depth, channel width, and bed slope performed in 49 reaches of some rills having a step-pool bed. A relationship between the velocity profile, the channel slope, and the flow Froude number was established. The analysis showed that the Darcy-Weisbach friction factor can be accurately estimated by the proposed theoretical approach based on a power-velocity profile. The Darcy-Weisbach friction factor values related to rills with step-pool sequences, on average, are higher than those related to rills without step pools, signifying that rills where step-pool sequences occur are characterized by a total resistance (grain and morphological) that is higher than grain resistance. Finally, this investigation showed that step pools that maximize flow resistance may develop at Froude numbers below the range at which step pools may form as antidunes.
机译：瑞尔在形态上演变，rill通道几何形状的调整影响速度，放电和坡度之间的关系。阶梯池中的流动抵抗主要是由于形成机制，并且相比，晶粒抗性具有较小的意义。以前的研究已经专门用于晶粒电阻条件并使用流流程方程进行。在该研究中，通过施加尺寸分析和自相似理论推导的新的流动性等式，应用于阶梯池通道中的rill流程。首先，使用不完全的自相似假设来建立电流速度曲线，其整合给出了达西 - Weisbach摩擦因子的理论表达。然后通过测量流速，水深，通道宽度和床斜率的测量来测试推导的理论电阻方程，在49到达一些具有梯级泳池床的植物中进行测试。速度曲线，沟道斜率和流动FROUDE号之间的关系建立。该分析表明，基于功率集速度的提出的理论方法，可以准确地估计Darcy-Weisbach摩擦因子。与没有步进池的梯级序列的侏脉摩擦系数值与梯级池有关的摩西 - Weisbach摩擦因子值，从没有阶梯池的情况表明发生阶梯池序列的植物，其特征在于通过总阻力（谷物和形态）这高于晶粒抗性。最后，该研究表明，最大化流动阻力最大化的步骤池可能在下面的范围内的弗劳德数字中发育，其阶梯池可以形成为安天云。

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