avalanches are abundant in the natural environment on a very wide
range of length scales and occur when a layer of granular material
becomes unstable. In the geophysical context rock-falls, landslides
and snow slab avalanches may set up to 10 billion cubic metres of
material in motion, whilst in industrial flows in silos, hoppers,
rotating drums or on slag heaps the volume of material is of the
order of several cubic centimetres to several hundreds of cubic
metres. Despite the enormous difference in length scales the
dominant physical mechanisms that drive the flow are
I am interested
in developing and extending mathematical models that describe the
complete avalanche motion from initiation, on a steep slope, to
run-out on a shallow slope. Many interesting features can be
observed, such as the formation of shock waves (above). The
avalanche enters from the top-right at high speed and is rapidly
brought to rest by a wall that is out of shot at the bottom-left
side, a shock wave forms and propagates upslope at almost constant
speed. As the material crosses the shock the avalanche thickness
increases by a factor of twelve. An animated version can be
seen by clicking on one of the following links (RealPlayer) (Mpeg) or (Windows Media Player).
PublicationsGray, J.M.N.T. & Hutter, K. (1998). Physik granularer Lawinen. Physikalische Blatter 54(1), 37-43.
Gray, J.M.N.T., Wieland, M. & Hutter K. (1999). Free surface flow of cohesionless granular avalanches over complex basal topography. Proc. Roy. Soc. 445 , 1841-1874.
Wieland, M., Gray, J.M.N.T. & Hutter K. (1999). Channelised free surface flow of cohesionless granular avalanches in a chute with shallow lateral curvature. J. Fluid. Mech. 392 , 73-100. (pdf)
Gray J.M.N.T., Tai Y.-C. & S. Noelle (2003) Shock waves, dead-zones and particle-free regions in rapid granular free surface flows. J. Fluid Mech. 491, 161-181. (pdf)
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