University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Doctoral Thesis:
Markus Wawra
(2010):
Numerical Modelling of Snow Avalanches
Interaction between Granular Flow and Obstruction.
Doctoral Thesis - Studienabteilung,
BOKU-Universität für Bodenkultur,
pp 109.
UB BOKU
obvsg
FullText
- Abstract:
- The interaction between granular flow and obstructions of different shape is investigated in this thesis. Two different approaches are applied to model the granular material numerically, i.e. a continuum mechanical model based on Savage-Hutter theory and a discontinuum approach based on the Discrete Element Method (DEM). The continuum mechanical model of Savage and Hutter has been widely used for avalanche simulation. The depth-integrated formulation is mainly applicable for shallow flow. This condition is not strictly fulfilled if obstructions with steep fronts, like walls or dams, are hit, since material is accumulated in front of the obstruction. The limitations of the existing model are discussed and some approaches to model the obstructions are studied. Further, the numerical solver, the NOC-scheme (Non-Oscillatory Central Difference) with TVD-limiter (Total Variation Diminishing) is extended by the Adaptive-Mesh-Refinement method (AMR), which provides local grid refinement. The suitability of the extended model is discussed for different obstructions and compared to experiments. As an alternative, the approach based on DEM is discussed. The model is programmed in the commercial software PFC3d. The advantage of this method is the completely three-dimensional modelling of the mass. The granular mass is simulated by small balls and the motion and the interaction among each other is described by simple physical laws. The large number of balls requires high computational effort. Additionally, the impact forces of the granular material on the obstruction are computed for both models.
- Betreuer: Wu Wei