Aa. Kassem et Mh. Chaudhry, COMPARISON OF COUPLED AND SEMICOUPLED NUMERICAL-MODELS FOR ALLUVIAL CHANNELS, Journal of hydraulic engineering, 124(8), 1998, pp. 794-802
Citations number
20
Categorie Soggetti
Water Resources","Engineering, Civil","Engineering, Mechanical
Contrary to general statements in the literature, the investigations r
eported in this paper show that semicoupled models are not necessarily
unstable and give results comparable to those of coupled models. For
this purpose, a two-dimensional model is developed to calculate bed va
riations in alluvial channels. Vertically averaged Navier-Stokes equat
ions in transformed coordinates are numerically solved in conjunction
with the sediment transport equation for the bed load. These equations
are solved simultaneously in a fully coupled model and separately in
a semicoupled model using the Beam and Warming alternating-direction i
mplicit scheme. Both models are applied to predict bed-level changes d
ue to sediment overloading and sediment shut-off. The computed results
compare satisfactorily with the experimental results obtained in a la
boratory flume. The results obtained by the semicoupled model are rela
tively close to that of the fully coupled model. Because the former al
gorithm permits any sediment formula and armoring effect to be easily
incorporated, the semicoupled model appears to be more attractive for
general applications to real-life systems than the coupled model.