Dam-Break Wave-Front Celerity

Abstract

This work is concerned with the role that friction and inertia effects can play on the magnitude of dam-break wave-front celerity. Classic analytical solutions are presented. A large collection of experimental data is used, covering a wide range of different initial conditions: fixed bed or mobile bed (five types of bed material), dry or wet bed downstream, and with or without bed step. To overcome the limitations of analytical solutions, a numerical model is used. The model is based on the shallow-water approach with contact-load dominated sediment transport, and it makes use of developments recently made in the study of sheet flows. The analytical and numerical results are compared with experimental data. It was found that the celerity is mainly dictated by the friction coefficient, by the sediment inertia, by the initial downstream water depth, and by the initial bed step height. For good data fitting, the friction coefficient must be influenced by the type of bed, fixed or mobile. In the latter, the coefficient must vary with the bed material characteristics. The dissimilarities between the experimental, analytical, and numerical results are interpreted.