Title Interplay of entrainment and rheology in snow avalanches; a numerical study
Author Issler, D.; Pastor Pérez, M.
Author Affil Issler, D., Norges Geotekniske Institutt and International Centre for Geohazards, Oslo, Norway. Other: Universidad Politécnica de Madrid, Spain
Source Annals of Glaciology, 52(58), p.143- 147, . Publisher: International Glaciological Society, Cambridge, United Kingdom. ISSN: 0260-3055
Publication Date 2011
Notes In English. 16 refs. GeoRef Acc. No: 310200
Index Terms avalanches; erosion; friction; mass movements (geology); rheology; sediment transport; cohesion; shear stress; simulation; environment simulation; slopes; snow; snow cover; velocity; equations; erosion rates; finite difference analysis; interpolation; mass movements; motions; numerical models; one-dimensional models; shear strength; transport
Abstract A one-dimensional evolution equation for the slope-normal velocity profile of a streamwise uniform avalanche over an entrainable bed is derived. The boundary conditions are no slip at the bed, a stress-free surface and constant bed shear stress equal to the shear strength of the snow cover. The resulting equation is solved numerically by means of finite differences on a regular gridwith a superposed fine grid near the erosion front that is adjusted at each time-step. The first exploratory simulations yield realistic entrainment rates and show that the entrainment rate tends towards a constant value while the flow depth and the velocity increase linearly with time for all investigated rheologies. It is shown that there indeed exists a rheology-independent asymptotic solution to the equation of motion of an entraining slab if the bottom friction is equal to the bed shear strength; the asymptotic acceleration is found to be half the downslope gravitational acceleration. The model can easily be extended to general path profiles, non-uniform flows and variable snow properties.
Publication Type journal article
Record ID 65007363