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首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >Partitioning resistance to overland flow on rough mobile beds
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Partitioning resistance to overland flow on rough mobile beds

机译：在粗糙的移动床上对水流的分配阻力

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For overland flows transporting predominantly bed load over rough mobile beds without rainfall, resistance to flow f may be divided into four components: surface resistance f(s), form resistance f(f), wave resistance f(w), and bed-mobility resistance f(m). In this study it is assumed that f=f(s)+f(f)+f(w)+f(m), and an equation is developed for each component. The equations for f(s) and f(f) are borrowed from the literature, while those for f(w) and f(m) are developed from two series of flume experiments in which the beds are covered with various concentrations of large-scale roughness elements. The first series consists of 65 experiments on fixed beds, while the second series contains 194 experiments on mobile beds. All experiments were performed on the same slope (S = 0.114) and with the same size of sediment (D = 0.00074 m). The equations for f(w) and f(m) are derived by a combination of dimensional analysis and regression analysis. The analyses reveal that the major controls of f(w) and f(m) are the Froude number F and the concentration of the roughness elements C-r. When the equations for f(w) and f(m) are summed, the C-r terms cancel out, leaving f(w+m) = 0.63F(-2). An equation is developed that predicts total f(w) and the contributions of f(s), f(f), f(w) and f(m) to f are computed from the series 1 and 2 experiments. An analysis of the first series reveals that in clear-water flows over fixed beds, f(w) accounts for 52 per cent off. A similar analysis of the second series indicates that in sediment-laden flows over mobile beds f. comprises 37 per cent and f. 32 per cent off, so that together f. and f. account for almost 70 per cent of f. Finally, regression analyses indicate that where F > 0.5, f(w) and f(m) each vary with F-2 and f(w)/f(m) = 1.18. The equation developed here for predicting total f applies only to the range of hydraulic, sediment, and bed roughness conditions represented by the experimental data. With additional data from a broader range of conditions the same methodology as employed here could be used to develop a more general equation. Copyright (c) 2006 John Wiley & Sons, Ltd.
机译：对于主要在没有降雨的粗糙移动床上运输河床荷载的陆上水流，水流阻力f可分为四个分量：表面阻力f（s），形状阻力f（f），波浪阻力f（w）和床层流动性电阻f（m）。在这项研究中，假设f = f（s）+ f（f）+ f（w）+ f（m），并且为每个分量建立了一个方程。 f（s）和f（f）的方程式是从文献中借来的，而f（w）和f（m）的方程式则是从两个系列的水槽实验中得到的，在这些实验中，床层覆盖了各种浓度的比例粗糙度元素。第一个系列包含65个固定床实验，而第二个系列包含194个移动床实验。所有实验均在相同的坡度（S = 0.114）和相同的沉积物尺寸（D = 0.00074 m）下进行。 f（w）和f（m）的方程是通过将维分析和回归分析相结合而得出的。分析表明，f（w）和f（m）的主要控制因素是弗洛德数F和粗糙度元素C-r的浓度。当将f（w）和f（m）的等式求和时，C-r项抵消，剩下f（w + m）= 0.63F（-2）。建立了一个预测总f（w）的方程，并从系列1和2实验计算出f（s），f（f），f（w）和f（m）对f的贡献。对第一个系列的分析表明，在固定床上的清水流中，f（w）减少了52％。对第二个系列的类似分析表明，在充满泥沙的流动床f上。包括37％和f。 32％的折扣，使在一起f。和f。占f的近70％。最后，回归分析表明，当F> 0.5时，f（w）和f（m）分别随着F-2和f（w）/ f（m）= 1.18而变化。此处开发的用于预测总f的方程式仅适用于由实验数据表示的水力，沉积物和床层粗糙度条件的范围。利用来自更广泛条件的其他数据，可以使用此处采用的相同方法来开发更通用的方程式。版权所有（c）2006 John Wiley＆Sons，Ltd.

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