Item: Avalanche simulation with samos-at
Title: Avalanche simulation with samos-at
Proceedings: International Snow Science Workshop, Davos 2009, Proceedings
Authors: Peter Sampl1 and Matthias Granig2 1 AVL List GmbH, Graz, Austria 2 Stabstelle Lawinensimulation, Schwaz, Austria
Abstract: The simulation software SAMOS for dry snow avalanches has been used by the Austrian Service for Torrent and Avalanche Control since 1999. The software was based on a twodimensional, depth-averaged model with Coulombian and turbulent bottom friction for the dense flow part and on a three-dimensional mixture-model for air and ice-particles, which form the powder snow part. The mixture model involved separate mass-balances for the air and ice-particles and one single balance for the momentum. Additional balances for the turbulent energy and dissipation rate were considered. The amount of powder snow generated from the dense flowing snow was predicted assuming an analogy of momentum- and mass-transfer above the dense-flow-surface. A triangular grid, moving with the flowing mass over the terrain surface, was used for the numerical solution of the dense-flow equations in Lagrangean formulation, while a three-dimensional, non-moving (Eulerian) grid, adapted to the terrain surface, was employed to solve the equations for the air-and-ice mixture. An improved version, SAMOS-AT, has been completed in 2007. The dense flow friction model was changed, so that the turbulent friction part depends also on the flow-depth. The mixture-model for the powder snow part was replaced by a full two-phase-model for air and ice-particles, with separate mass and momentum balances. A smoothed-particle hydrodynamics method is used now to solve the dense-flow-equations. The improved model is described in this paper.
Keywords: avalanche dynamics, simulation, dense flow avalanches, powder avalanches
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