Unified View of Sediment Transport by Currents and Waves. II: Suspended Transport
Unified View of Sediment Transport by Currents and Waves. II: Suspended Transport
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DOI：
10.1061/(asce)0733-9429(2007)133:6(668
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发表时间：
2007-06
影响因子：
2.4
通讯作者：
L. Rijn
中科院分区：
文献类型：
--
作者：
L. Rijn
本文讨论了河流和海岸流中的悬浮泥沙输运问题。高质量的河流和海岸流的现场数据已被选择和聚类成四个粒径类60-100，100-200，200-400，和400-600米。悬浮泥沙输运被发现是强烈依赖于粒径和流速。在海岸带的悬浮泥沙输运被认为是强烈依赖于相对波高Hs/h，特别是在0.2-0.5米/秒的范围内的流速。采用时均的波浪周期对流扩散方程，计算了水流和波浪共同作用下的时均含沙量剖面。絮凝、受阻沉降和分层效应用相当简单的表达式表示。床面切应力是基于一个新的床面粗糙度预测。参考浓度函数已被重新校准，结合稳定和振荡流的实验室和现场数据。计算出的输运率与0.6-1.8 m/s范围内的速度和60-600 m范围内的沉积物的测量值在2倍内相当吻合。所提出的方法在0.6 m/s的低速范围内预测不足。提出了一个新的简化输运公式，可用于快速估算悬浮输运。基于Bagnold能量概念的河流冲刷输沙模型表明，水流可以输运大量的极细泥沙粘土和极细粉砂。
The problem of suspended sediment transport in river and coastal flows is addressed. High-quality field data of river and coastal flows have been selected and clustered into four particle size classes 60-100, 100-200, 200-400, and 400-600 m. The suspended sand transport is found to be strongly dependent on particle size and on current velocity. The suspended sand transport in the coastal zone is found to be strongly dependent on the relative wave height Hs/h, particularly for current velocities in the range 0.2-0.5 m/s. The time-averaged over the wave period advection-diffusion equation is applied to compute the time-averaged sand concentration profile for combined current and wave conditions. Flocculation, hindered settling, and stratification effects are included by fairly simple expressions. The bed-shear stress is based on a new bed roughness predictor. The reference concentration function has been recalibrated using laboratory and field data for combined steady and oscillatory flow. The computed transport rates show reasonably good agreement within a factor of 2 with measured values for velocities in the range of 0.6-1.8 m/s and sediments in the range of 60-600 m. The proposed method underpredicts in the low-velocity range 0.6 m/s. A new simplified transport formula is presented, which can be used to obtain a quick estimate of suspended transport. The modeling of wash load transport in river flow based on the energy concept of Bagnold shows that an extremely large amount of very fine sediment clay and very fine silt can be transported by the flow.