Difference in the bed load transport of graded and uniform sediments during floods: An experimental investigation

Khosravi, Khabat, Chegini, Amir, Binns, Andrew, Daggupati, Prasad and Mao, Luca (2019) Difference in the bed load transport of graded and uniform sediments during floods: An experimental investigation. Hydrology Research, 50 (6). pp. 1645-1664. ISSN 0029-1277

Full content URL: https://doi.org/10.2166/nh.2019.078

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Difference in the bed load transport of graded and uniform sediments during floods: An experimental investigation
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Abstract

The objective of this study was to experimentally evaluate the difference in the transport of uniform (5.17, 10.35, 14, 20.7 mm) and graded sediment (mixture of these rounded particles with equal weight proportions) under different unsteady flow hydrographs in a 12 m long, 0.5 m wide and deep glass-walled flume. There was a lag time between fractions and uniform particles, such that peaks of coarser and finer fraction particles occurred before and after the peak of uniform sediment with the same size, respectively. Comparison between uniform particles and fractions in graded sediment showed that the sediment transport rate of fine and coarse fractions was lower and higher than their counterpart uniform particles, respectively. Overall, the uniform particles demonstrated a clockwise hysteresis loop and graded sediment had a counterclockwise hysteresis loop. The mobility of coarser fractions increased during the rising limb of hydrograph, whereas the mobility of finer fractions increased during the falling limb. In general, the mobility of coarse fractions increased and that of fine fractions reduced. Result of transported sediment showed that average particle size collected in traps (Db50) was coarser than bed material (Ds50) on both limbs. The relative transport ratio for uniform and graded sediment is higher and lower than 1, respectively.

Keywords:bed load, experimental investigation, graded sediment, hysteresis loop, mobility, unsteady flow hydrograph
Subjects:F Physical Sciences > F820 Geomorphology
Divisions:College of Science > School of Geography
ID Code:38211
Deposited On:31 Oct 2019 09:01

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