Enhanced bed load sediment transport by unsteady flows in a degrading channel

Zhijing Li, Honglu Qian, Zhixian Cao, Huaihan Liu, Gareth Pender, Penghui Hu

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)
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Abstract

Laboratory flume experiments were done to investigate bed load sediment transport by both steady and unsteady flows in a degrading channel. The bed, respectively composed of uniform sand, uniform gravel, or sand-gravel mixtures, always undergoes bulk degradation. It is found that both uniform and non-uniform bed load transport is enhanced greatly by unsteady flows as compared to their volume-equivalent steady flows. This enhancement effect is evaluated by means of an enhancement factor, which is shown to be larger with a coarser bed and lower discharges. Also, the fractional transport rates of gravel and sand in non-uniform sand-gravel mixtures are compared with their uniform counterparts under both steady and unsteady flows. The sand is found to be able to greatly promote the transport of gravel, whilst the gravel considerably hinders the transport of sand. Particularly, the promoting and hindering impacts are more pronounced at lower discharges and tend to be weakened by flow unsteadiness.
Original languageEnglish
Pages (from-to)327-339
Number of pages13
JournalInternational Journal of Sediment Research
Volume33
Issue number3
Early online date9 Mar 2018
DOIs
Publication statusPublished - Sept 2018

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