IAHR, founded in 1935, is a worldwide independent member-based organisation of engineers and water specialists working in fields related to the hydro-environmental sciences and their practical application. Activities range from river and maritime hydraulics to water resources development and eco-hydraulics, through to ice engineering, hydroinformatics, and hydraulic machinery.
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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Sediment management and morphodynamics : Effects of particle shapes and sizes on vertical sortings
Effects of particle shapes and sizes on vertical sortings
Gravel-bed rivers are composed of particles of various shapes and sizes. The shapes and sizes of particles in the gravelbed
river have great influences on sediment transport and river bed variation. Numerical methods of sediment transport
and river bed variation in gravel-bed rivers must consider effects of particles shapes properly. This paper mainly
demonstrates the effects of particle shapes on vertical sorting by comparing motions of spheres and gravels in numerical
slope failure experiments in the water. The numerical experimental results demonstrated that the angle of repose of gravel
particles was larger than that of spheres due to engagement effects of gravel particles. Moreover, slope failures of both
upper part and lower part of sphere-particles stratum progressed gradually. On the other hand, the slope failure of lower
part of gravel particles progressed more slowly compared to sphere particles due to large engagement effects among
particles. Then upper particles of gravel fell down in a relatively long time. In both cases of spheres and gravels, large
particles tended to move parallel to the channel bed, but small particles tended to drop in the lower part of the channel.
Consequently, the vertical sorting made particles on the slope surface larger. Particles on the surface of the sphere slope
became larger than those of gravels. Moreover, the porosity of gravels in the moving layer was larger than that of spheres.
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Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Sediment management and morphodynamics
Date Published : 17/08/2015
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