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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Sediment management and morphodynamics : Interactions between coarse and fine particles & their influences on the bimodal bed load transport
Interactions between coarse and fine particles & their influences on the bimodal bed load transport
ABSTRACT In order to study the impacts of the interactions between coarse and fine particles on the non-uniform sediment transport, the real time simultaneous monitoring of the sediment load, the grain composition and the fluctuating velocity near the bed have been carried out, which is based on the technologies of the instantaneous bed load acquisition, image identification and Doppler velocity measurement. Aimed at the non-uniform sediment with bimodal pattern, 211sets of flume experiment for bed load transport have been conducted. Analysis of the experimental results indicates that the random fluctuation of the bed load transport quantity seems to have some relevant response to the velocity fluctuation caused by turbulence burst near the bed. The fine particles on the bed mostly remain continuously transporting in the process; however, the transport of the coarse particles is always paroxysmal, abiding by three modes: priming, triggering and breaking. If the differential of diameter between coarse and fine particles is obvious, the coarse particles transport may have supernormal performance, which results from the incenting, colliding and unbinding effects of the fine particles on the coarse particles. Under the same flow intensity, the transport rate presents hump curve changes with the decrease of the thickness ratio of the coarse to the fine. Only if the ratio£®¶«c£©is appropriate may the transport rate of the non-uniform bed load reach to the peak, which is higher than any transport rate of the uniform coarse or fine sediment in this non-uniform sediment. Such finding is of important merit to the study of non-uniform sediment transport in alluvial rivers.
File Size : 1,043,060 bytes
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Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Sediment management and morphodynamics
Date Published : 18/08/2015
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