ON VARIOUS DISPERSION MODELS FOR SIMULATING FLOW AT CHANNEL BENDS

In this paper, by using depth-averaged equations, three different dispersion models for
simulating flow at channel bends are presented and compared. Two of these models employ power
law velocity distributions for longitudinal velocity components and linear distributions for
transverse component, and the last model employs logarithmic velocity distributions in transverse
and longitudinal directions. The first two models differ in how the effect of secondary flow is
evaluated. Boundary-fitted curvilinear coordinates in conjunction with finite-volume method have
been used for discretization of the governing equations. The numerical results are compared with
available experimental data of a 270o bend. The study shows that a power law distribution for
streamwise velocity with a suitable estimation of secondary flow intensity gives the best results for
simulation of two-dimensional depth-averaged flow in open channel bends among the models
studied. This model can successfully predict the most important characteristics of flow in curved
channels.