Computer modelling of two-stage meandering channel flows

Prediction of flow in two-stage meandering channels for overbank flow was undertaken using a commercially available computer model. The software, TELEMAC-2D, solves the depth-averaged Navier–Stokes equations with non-structured grids for free surface flow. The model results are compared with the experimental data obtained from the UK Flood Channel Facility. Advection schemes offered in TELEMAC-2D are examined for their influence upon a bed friction coefficient. The effect of mesh resolution on solution accuracy is also investigated. The simulated distributions of depth-averaged velocity and boundary shear stress are also used to investigate the accuracy of the TELEMAC-2D prediction by comparison with the experimental data. The 1D and local Manning coefficients calculated using the experimental data are compared with the calibrated Manning coefficient. The results show that the choice of Manning coefficient is vital for an accurate prediction of overbank flow in two-stage meandering channels, and that transverse turbulence diffusion is not so significant.