University of Birmingham > Talks@bham > Theoretical Physics Seminars > Melting in Ice Avalanches

Melting in Ice Avalanches

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  • UserDr Barbara Turnbull, U of Nottingham
  • ClockThursday 15 March 2012, 13:45-15:00
  • HouseTheory Library.

If you have a question about this talk, please contact Dr Dimitri M Gangardt.

Avalanches are a fascinating natural phenomenon that pose an evolving risk as increasing numbers of people take on the challenges of winter climbing and ski-touring. The hazard is also changing as climate patterns shift, bringing into question the use of historical records in assessing risk. There is a strong need for a physics-based approach to understanding the key processes that influence the dynamics of these flows, so that potential run out distances and impact pressures can be determined. This talk will focus upon the hazard posed by rock & ice avalanches. These can arise from collapsing glacier séracs, rock-faces previously stabilised by permafrost or the activity of an ice-capped volcano. The extraordinary mobility of the extreme event at Karmadon, Russian Caucasus, in September 2002 brought ice-bearing flows into sharp focus. Here, we explore the hypothesis that localised melting within this ice-bearing flow may significantly alter the dynamic characteristics compared to a classical dry granular shear flow. The dynamic effects of melting processes that lead to wetted particle surfaces are investigated in a laboratory experiment. The two inter-related processes within this flow are i) the granular collisions that lead to melting and thus wetted particle surfaces and ii) the lubrication and capillary actions arising from wetting that fundamentally alter the nature of inter-particle contacts and thus the dynamics.

Barbara Turnbull has been a lecturer in Environmental Fluid Mechanics at Nottingham University since 2008. Prior to this, she undertook her PhD research at the Swiss Federal In- stitute for Snow and Avalanche Research, investigating powder snow avalanche dynamics in the laboratory and in the field, and developing theory to describe them. After finishing her PhD in Dundee with Prof. Peter Davies, she worked with Jim McElwaine (Cambridge University) on a large experiment looking at shocks in high-speed, un-steady granular flows, and with Prof. Michel Louge (Cornell University) investigating explosive, vortex-driven erosion into the heads of particle-driven gravity currents. She is currently in the process of building a small, avalanche-focused research team.

This talk is part of the Theoretical Physics Seminars series.

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