Granulation of snow: From tumbler experiments to discrete element simulations
Metadata only
Date
2015-06Type
- Journal Article
ETH Bibliography
no
Altmetrics
Abstract
It is well known that snow avalanches exhibit granulation phenomena, i.e., the formation oflarge and apparently stable snow granules during the flow. The size distribution of the granules has aninfluence on flow behavior which, in turn, affects runout distances and avalanche velocities. The underlyingmechanisms of granule formation are notoriously difficult to investigate within large-scale fieldexperiments, due to limitations in the scope for measuring temperatures, velocities, and size distributions.To address this issue we present experiments with a concrete tumbler, which provide an appropriate meansto investigate granule formation of snow. In a set of experiments at constant rotation velocity with varyingtemperatures and water content, we demonstrate that temperature has a major impact on the formationof granules. The experiments showed that granulesonly formed when the snow temperature exceeded −1°C. No evolution in the granule size was observed at colder temperatures. Depending on the conditions,different granulation regimes are obtained, which are qualitatively classified according to their persistenceand size distribution. The potential of granulation of snow in a tumbler is further demonstrated by showingthat generic features of the experiments can be reproduced by cohesive discrete element simulations.The proposed discrete element model mimics the competition between cohesive forces, which promoteaggregation, and impact forces, which induce fragmentation, and supports the interpretation of thegranule regime classification obtained from the tumbler experiments. Generalizations, implications for flowdynamics, and experimental and model limitations as well as suggestions for future work are discussed. Show more
Publication status
publishedExternal links
Journal / series
Journal of Geophysical Research: Earth SurfaceVolume
Pages / Article No.
Publisher
American Geophysical UnionSubject
granulation of snow; avalanche; snow temperature; cohesive granular materialOrganisational unit
09795 - Gaume, Johan / Gaume, Johan
More
Show all metadata
ETH Bibliography
no
Altmetrics