Item: GRAIN FLOW THEORY AND SNOW AVALANCHE RHEOLOGY
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Title: GRAIN FLOW THEORY AND SNOW AVALANCHE RHEOLOGY
Proceedings: International Snow Science Workshop 2024, Tromsø, Norway
Authors:
- Perry Bartelt [ WSL Institute for Snow and Avalanche Research SLF ]
- Lukas Stoffel [ WSL Institute for Snow and Avalanche Research SLF ]
- Marc Christen [ RAMMS AG Davos Wiesen ]
- Yves Bühler [ WSL Institute for Snow and Avalanche Research SLF ]
Date: 2024-09-23
Abstract: This paper explores the application of grain flow theory to snow avalanche dynamics, focusing on the interrelation between shear stress and fluctuation energy. The study employs a system of differential equations to model the mean velocity (U) and fluctuation energy (R) within snow avalanches. The key physical constraint highlighted is the relationship dR · S = −R0 · dS, which provides a physical constraint on the complex relationship between avalanche shear stress and the production of fluctuation energy. When fluctuation energy is produced by shearing, it generates not only directionless random kinetic energy but also directional energy fluxes that alter the configuration of the granular ensemble, leading to changes in shear stress. The analysis of the R-U phase plane reveals that avalanche behavior can be characterized by equilibrium points that shift with slope angle, highlighting the role of fluctuation energy in determining the flow regime. The R-U phase plane not only advances our understanding of avalanche dynamics but also facilitates the examination of flow regime transitions, driven by changes in the potential energy of the granular ensemble, and the emergence of different avalanche types.
Object ID: ISSW2024_P2.9.pdf
Language of Article: English
Presenter(s): Perry Bartelt
Keywords: Avalanche dynamics, shear stress, grain flow theory, flow regime, flow regime transitions.
Page Number(s): 360 - 365
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