Bend-flow simulation using 2D depth-averaged model

The purpose of this paper is to present a 2D depth-averaged model for simul ating and examining flow patterns in channel bends. In particular, this pap er proposes a 2D depth-averaged model that takes into account the influence of the secondary flow phenomenon through the calculation of the dispersion stresses arisen from the integration of the products of the discrepancy be tween the mean and the true velocity distributions. The proposed model uses an orthogonal curvilinear coordinate system to efficiently and accurately simulate the flow field with irregular boundaries. As for the numerical sol ution procedure, the two-step split-operator approach consisting of the dis persion step and the propagation step with the staggered grid is used to nu merically solve the flow governing equations. Two sets of experimental data from de Vriend and Koch and from Rozovskii were used to demonstrate the mo del's capabilities. The former data set was from a mildly curved channel, w hereas the latter was from a sharply curved channel. The simulations consid ering the secondary flow effect agree well with the measured data. Furtherm ore, an examination of the dispersion stress terms shows that the dispersio n stresses play a major role in the transverse convection of the momentum s hifting from the inner bank to the outer bank for flows in both mild and sh arp bends.