Simulación física y numérica de las avalanchas de nieve en Francia

Abstract

In this paper are presented and described the main characteristics of the different kind of snow avalanches. We distinguishes two great families : dense and powder avalanches. Their releasing conditions are reminded and their dynamics and effects are described. A modelling based on Saint Venant equations (completed by a Bingham reological model) is proposed for the dense avalanches. Concerning powder avalanches their similarity with gravity currents allows to undertake a physical modelling. This physical modelling is succinctly described and the densimetric Froude similarity critérium is presented. The numerical modelling of this kind of avalanches (based on Navier-Stokes equations and on a turbulence model) is shown . The comparison between the two models is made in the case of aturbidity current. The numerical modelling allows to find global characteristics of the flow (such height and velocity of the avalanche front) and allows especially to access to the internal variables (pressure, concentration, velocity and turbulence characteristics)