Item: NEW INSIGHTS INTO SNOW AVALANCHE DYNAMICS AND ENTRAINMENT MECHANISMS FROM DEPTH-RESOLVED PARTICLE-BASED SIMULATIONS
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Title: NEW INSIGHTS INTO SNOW AVALANCHE DYNAMICS AND ENTRAINMENT MECHANISMS FROM DEPTH-RESOLVED PARTICLE-BASED SIMULATIONS
Proceedings: International Snow Science Workshop 2024, Tromsø, Norway
Authors:
- Johan Gaume [ ETH Zurich, Switzerland ] [ WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland ] [ Climate Change, Extremes and Natural Hazards in Alpine Regions Research Centre CERC, Davos, Switzerland ]
- Camille Ligneau [ WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland ]
- Camille Huitorel [ ETH Zurich, Switzerland ] [ WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland ] [ Climate Change, Extremes and Natural Hazards in Alpine Regions Research Centre CERC, Davos, Switzerland ]
- Xingyue Li [ Tongji University, China ]
- Michael Kyburz [ ETH Zurich, Switzerland ] [ WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland ] [ Climate Change, Extremes and Natural Hazards in Alpine Regions Research Centre CERC, Davos, Switzerland ]
- Betty Sovilla [ WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland ]
- Lars Blatny [ ETH Zurich, Switzerland ] [ WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland ] [ Climate Change, Extremes and Natural Hazards in Alpine Regions Research Centre CERC, Davos, Switzerland ]
- Hervé Vicari [ ETH Zurich, Switzerland ] [ WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland ] [ Climate Change, Extremes and Natural Hazards in Alpine Regions Research Centre CERC, Davos, Switzerland ]
Date: 2024-09-23
Abstract: In mountainous regions, snow avalanches pose significant threats to both populations and infrastructure. As the flow progresses, it can accumulate additional mass by entraining bed material along its path, thereby amplifying its destructive potential. Volume increases of over tenfold the initial volume have been documented from avalanche observation and measurements. Entrainment is usually accounted for in depth-averaged models through a source term in the mass conservation equation and simplified entrainment criteria. However, quantitative assessment of erosion/entrainment rates with various flow types and bed material properties has seldomly been explored under well-controlled conditions. In this work, we investigate avalanche dynamics as well as erosion/entrainment mechanisms on the basis of depth-resolved particle-based simulations. Through such a modeling approach, processes like frontal ploughing, basal abrasion as well as erosion-deposition waves naturally emerge. Our findings highlight that, the interaction of the flow with the initially static bed material may have multiple and diverse effects on the flow behavior. First, the bed material can be eroded, but only partially entrained in the flow. Second, while the flow mobility is generally reduced by the presence of the bed, it may be enhanced in some cases due to the mechanical weakening of the bed. Finally, we propose a relationship linking the entrainment rate to a dimensionless parameter that compares the flow-induced stress to the bed shear resistance. This work contributes to a better understanding of the dynamics of snow avalanches and entrainment process and can lead to a refinement of depth-averaged formulations for practical purposes. Future research should consider factors such as rate-dependent snow rheology, air pore pressure and bed fluidization mechanisms to further refine our understanding and predictive capabilities in avalanche modeling.
Object ID: ISSW2024_O2.5.pdf
Language of Article: English
Presenter(s):
Keywords: avalanche dynamics, erosion, entrainment, modeling, Material Point Method, Discrete Element Method
Page Number(s): 306 - 313
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