Bed-Load Transport
Bed-Load Transport
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床载运输
DOI：
10.1007/978-3-642-19062-9_5
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发表时间：
2014
影响因子：
2.4
通讯作者：
["S. Dey
中科院分区：
文献类型：
--
作者：
["S. Dey
泥沙运动的模式，即泥沙颗粒滑动，滚动，和/或旅行在连续的低跳接近床被称为推移质输运。本章介绍了推移质理论和推移质输沙率的计算公式。1879年，MP du Boys首次尝试预测推移质输沙率，他将推移质输沙率表示为过量床面剪切应力的函数，即床面剪切应力超过阈值床面剪切应力。此后，许多研究者提出了不同形式和系数的杜波依斯型方程。其他用于预测推移质输沙率的概念有：流量概念（Schoklitsch型）、流速概念、底形概念、概率概念（Einstein型）、确定性概念（Bagnold型）和等流度概念。此外，湍流唯象理论的应用为推移质输移的标度律提供了依据。本章的附加特点是讨论了颗粒跃移、泥沙分选、河床粗化和泥沙夹带推移质的可能性。文中还详细讨论了推移质对流速分布、紊动尺度和冯卡门常数的影响。通过算例说明了推移质输移量的计算方法。
The mode of sediment transport where the sediment particles slide, roll, and/or travel in succession of low jumps close to the bed is known as the bedload transport. In this chapter, theories of bedload and formulations to predict the bedload transport rate are presented. The pioneering attempt to predict the bedload transport rate was due to MP du Boys in 1879, who expressed bedload transport rate as a function of excess bed shear stress, that is the bed shear stress exceeding the threshold bed shear stress. Thereafter, number of researchers suggested du Boys-type equations making use of the excess bed shear stress in different forms and coefficients. Other concepts to predict the bedload transport rate are the discharge concept (Schoklitsch type), the velocity concept, the bedform concept, the probabilistic concept (Einstein type), the deterministic concept (Bagnold type), and the equal mobility concept. Besides, the application of the turbulence phenomenological theory provides the origin of the scaling law of the bedload transport. The additional features of this chapter are the discussion on particle saltation, sediment sorting, streambed armoring, and sediment entrainment probability to bedload. The effects of bedload on velocity distribution, length scales of turbulence, and von Kármán constant are also discussed in detail. The methods of computation of bedload transport are illustrated through worked-out examples.