A simple but applicable analytical model is presented to predict the lateral distribution of the depth-averaged velocity in meandering compound channels. The governing equation with curvilinear coordinates is derived from the momentum equation and the flow continuity equation under the condition of quasi-uniform flow. A series of experiments are conducted in a large-scale meandering compound channel. Based on the experimental data, a magnitude analysis is carried out for the governing equation,and two lower-order shear stress terms are ignored. Four groups of experimental data from different sources are used to verify the predictive capability of this model, and good predictions are obtained. Finally, the determination of the velocity parameter and the limitation of this model are discussed.
The governing equation of the discharge per unit width, derived from the flow continuity equation and the momentum equation in the vegetated compound channel, is established. The analytical solution to the discharge per unit width is presented,including the effects of bed friction, lateral momentum transfer, drag force, and secondary flows. A simple but available numerical integral method, i.e., the compound trapezoidal formula, is used to calculate the approximate solutions of the sub-area discharge and the total discharge. A comparison with the published experimental data from the U. K.Flood Channel Facility(UK-FCF) demonstrates that this model is capable of predicting not only the stage-discharge curve but also the sub-area discharge in the vegetated compound channel. The effects of the two crucial parameters, i.e., the divided number of the integral interval and the secondary flow coefficient, on the total discharge are discussed and analyzed.
