Geomorphic dam-break flows. Part II: numerical simulation

This paper presents the comparison between numerical results obtained with a conceptual model proposed in a companion paper and experimental results collected from previous studies. The numerical model is based on a finite difference approximation using the MacCormack scheme with a total variation diminishing high-resolution correction term for the mixture mass and momentum conservation equations and an artificial viscosity term for the sediment mass conservation equation. From the comparison between numerical and experimental results, it can be verified that the model generally gives results in good agreement with the experimental data and the wave structure is in accordance with what has been reported in previous studies. The estimation of model parameters based on existing sheet-flow data seems a promising way of developing models without arbitrary choice of values for tuning parameters. Some limitations can be identified, namely the equilibrium sediment transport approach implies that the model cannot simulate the hydraulic jump formed in the higher mobility bed for dry bed conditions. The use of a constant friction factor does not allow simulating the exact wave-front location for all instants in time.