Initiation of Bed Forms on a Flat Sand Bed
Initiation of Bed Forms on a Flat Sand Bed
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DOI：
10.1061/(asce)0733-9429(1996)122:6(301
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发表时间：
1996-06
影响因子：
2.4
通讯作者：
S. Coleman;B. Melville
中科院分区：
文献类型：
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作者：
S. Coleman;B. Melville
一系列 47 个床开发实验的结果与其他作者的适当实验结果相结合。人们发现，平面沙床上初始床波（称为沙子波）的产生是由沉积物的随机堆积引起的，随着更多的沉积物被堆积捕获，该堆积随后不断增长。当堆积物的高度接近床层粗糙度高度时，在下游的优选间距处会产生进一步的堆积物。如此生成的沙子波的波长 l 对所施加的床剪切应力相对不敏感，并且主要是沉积物尺寸 d g 的函数。该波长可以用经验公式(l/dg)R*c0.2= 10 2.5 来描述。从理论角度来看，这个波长可以通过重新评估理查兹的流动系统不稳定性分析来近似描述。人们发现波纹和沙丘都是由沙子小波发展而来的。
The results of a series of 47 bed development experiments are combined with appropriate experimental results of other authors. The generation of initial bed waves, termed sand-wavelets, on a plane sand bed is found to be instigated by the occurrence of a random pileup of sediment, this pileup subsequently growing as further sediment is trapped by the pileup. When the height of the pileup approaches the bed roughness height, further pileups are generated at preferred spacings downstream. The wavelength l of the sand-wavelets so generated is relatively insensitive to the applied bed shear stress and primarily a function of the size d g of the sediment. This wavelength can be described by the empirical formula (l/dg)R*c0.2= 10 2.5. From a theoretical viewpoint, this wavelength is approximately described by a reassessment of the flow system instability analyses of Richards. Both ripples and dunes are found to develop from the sand-wavelets.