Modélisation numérique des écoulements de laves torrentielles

Numerical modelling of debris flow dynamics

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Abstract

In order to predict complex transient debris flows we developed a numerical model based on shallow-water-equations. We consider only muddy debris flows whose simple shear behaviour is well represented by a Herschel-Bulkley model. In laminar regime, the wall friction force is assumed to be equal to the resistance of a steady uniform flow having same depth and mean velocity. The model parameters, deduced from the fluid behaviour, are estimated independently by rheometrical measurements. The main characteristics of our experimental transient flows, established in a laboratory flume, are in fairly good agreement with the numerical model predictions without any additional fitting.