水槽
泥沙输移
河床
过程线
地质学
推移质
沉积物
岩土工程
水文学(农业)
流量(数学)
水力学
高含沙水流
地貌学
机械
工程类
地表径流
物理
生态学
航空航天工程
生物
作者
Daniel G. Wren,Roger A. Kuhnle,Eddy J. Langendoen,Tate O. McAlpin
标识
DOI:10.1061/jhend8.hyeng-13769
摘要
Complex interactions between flowing water and bedforms in rivers with sand beds during changing flow rates may result in bedforms, flow resistance, and sediment transport rates that differ on the rising and falling limbs of flow hydrographs. To study this phenomenon, laboratory experiments based on six realistically shaped hydrographs with durations of 1–6 h in 1-h increments were performed in a recirculating flume at the United States Department of Agriculture-Agricultural Research Service (USDA-ARS) National Sedimentation Laboratory. Bed topography, water-surface slope, flow rate, and sediment transport rate were continuously monitored. Counterclockwise hysteresis between discharge and sediment transport rate as well as bedform dimensions were observed for all hydrograph lengths, and the magnitude of hysteresis was quantified. The amount of hysteresis in transport rate, bedform amplitude, and bedform length varied according to the length of the hydrograph, although the relationship was not monotonic. The Engelund–Hansen method was able to approximately predict sediment transport rates based on measured hydraulic parameters. Maximum bedform amplitudes increased with hydrograph length, while bedform lengths increased only minimally beyond the 4-h hydrograph period.
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