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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Sediment management and morphodynamics : Comparative evaluation of velocity distribution equations in sediment-laden flow
Comparative evaluation of velocity distribution equations in sediment-laden flow
Author : MOHSEN NASRABADI(1), MOHAMMAD HOSSEIN OMID(2) & ALI MAHDAVI MAZDEH(3)
ABSTRACT
Accurate estimation of the sediment rate is very important in sediment-laden flows. The velocity distribution is one of the
most important parameters to estimate the sediment rate. Until now, many equations have been introduced by many
researchers for estimating the velocity distribution in open channel flows. In this paper, eight proposed models have
been examined for the velocity distribution in sediment-laden flows by a comparison with selected datasets. Such
equations as power law, log law, modified log law, log-wake law, modified log-wake, log-modified wake, and parabolic
law have been evaluated. The accuracy of each equation has been assessed using some statistical indices, such as,
MAE, RMSE, and R2. Results have shown that logarithmic distribution only able to estimate accurately the velocity in the
inner region. Comparing the equations with experimental data and based on the statistical analysis, have shown that the
velocity values in both inner and outer regions are estimated with reasonable accuracy using log-wake velocity
distribution (with a relative error up to about 5%). This equation is recommended for calculating the suspended sediment
discharge. On the other hand, parabolic-law doesnĄ¯t have a good accuracy and it will cause large errors (with a relative
error up to about 17%). In addition, because of low sediment concentration in outer layer of sediment-laden flows, the
effect of suspended sediment in this layer becomes very low and can be ignored.
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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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