Dam break: validation of Cemagref's numerical models within the framework of CADAM

Abstract

CADAM (Concerted Action for Dam Break Waves) was funded by European Union in order to compare the numerical methods used to simulate the breaching of a dam and the downstream propagation of the wave created. The methodology used during the Concerted Action is summed up and the results obtained by Cemagref are presented on some specific case studies representative of the set of tests used. For the propagation wave, references may be analytical solutions, experiments or field observations. Only for the first case, it can be considered that numerical solution is close to the reference. For experiments and field cases, the physical processes show instabilities linked with the high turbulence of the flow which are not correctly described by the de Saint Venant equations. However, with convenient calibration of the Manning-Strickler coefficient, the calculation results are, in average, in agreement with observations; 2D models can more easily take into account local conditions. For breaching of a dam, only experimental data were available; the calculation results were very scattered and the more complex codes did not provide better results than the simpler models in all cases.