Berlin 2005 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 34: Poster
DY 34.99: Poster
Montag, 7. März 2005, 15:30–18:00, Poster TU D
Dynamics of granular avalanches caused by local perturbations — •Thorsten Emig1, Philippe Claudin2, and Jean-Philippe Bouchaud3 — 1Institut für Theoretische Physik, Universität zu Köln, Zülpicher Str. 77, 50937 Köln — 2Laboratoire de Physique et Mécanique des Milieux Hétérogènes, ESPCI, 10 rue Vauquelin, 75231 Paris Cedex 05, France — 3Service de Physique de l’État Condensé, Centre d’études de Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette Cedex, France
Surface flow of granular material is investigated within a continuum approach in two dimensions. The dynamics is described by the non-linear coupling between a mobile layer and an erodible bed of static grains. Following previous studies, we use mass and momentum conservation to derive St-Venant like equations for the evolution of the thickness of the mobile layer and the profile of the bed. This approach allows the rheology in the flowing layer to be specified independently, and we consider in details the two following models: a constant plug flow and a linear velocity profile. We study and compare these models for non-stationary avalanches triggered by a localized amount of mobile grains on a bed of initially constant slope. We solve analytically the non-linear dynamical equations by the method of characteristics. This enables us to investigate the temporal evolution of the avalanche size, amplitude and shape as a function of model parameters and initial conditions. In particular, we can compute their large time behavior as well as the condition for the formation of shocks.