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Potential flow models of suspension current air pressure

  • Barbara Turnbull (a1) and Jim N. McElwaine (a2)

Abstract

We present, analyse and discuss air-pressure data from finite-volume chute flows of dry fine snow in air. These experiments have the correct similarity criteria to model powder-snow avalanches and demonstrate the transition from a dense to a suspended flow. We measured the dynamic air pressure at the base of the flow, which features a marked negative pressure peak immediately behind the front. This feature is also seen in observations of natural powder-snow avalanches measured in Russia, Japan and Switzerland in direct numerical simulations of non-Boussinesq suspension flows and in ping-pong ball avalanches. This is evidence for large internal motions and suggests that there is a coherent vortex in the avalanche front. This can result in impact pressures many times larger than those expected from the mean flow velocity. We analyse the external air pressures using three models and show how the geometry and velocity of the flow can be found from this single air-pressure measurement. We also measured flow heights and speeds using image analysis and show that the speed is roughly independent of the slope angle and scales with the release size raised to the power 1/4, as predicted by similarity analysis for pseudo two-dimensional (2-D) flows.

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Copyright

References

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Ancey, C. 2004. Powder snow avalanches: approximation as non-Boussinesq clouds with a Richardson number-dependent entrainment function. J. Geophys. Res., 109(F1), F01005. (10.1029/2003JF000052.)
Ancey, C. 2007. Plasticity and geophysical flows: a review. J. Non-Newtonian Fluid Mech., 142(1–3), 435.
Batchelor, G.K. 1967. An introduction to fluid dynamics. Cambridge, Cambridge University Press.
Batchelor, G.K. 1989. A brief guide to two-phase flow. In Germain, P., Piau, M. and Caillerie, D., eds. Proceedings of the 17th International Congress on Theoretical and Applied Mechanics (ICTAM), 21–27 August 1988, Saint-Martin-d’He`res, France. Amsterdam, Elsevier, 2741.
Beghin, P., Hopfinger, E.J. and Britter, R.E.. 1981. Gravitational convection from instantaneous sources on inclined boundaries. J. Fluid Mech., 107, 407422.
Benjamin, T.B. 1968. Gravity currents and related phenomena, J. Fluid Mech., 31(2), 209248.
Britter, R.E. and Linden, P.F.. 1980. The motion of the front of a gravity current travelling down an incline. J. Fluid Mech., 99(3), 531543.
Brooke, B.T. 1968. Gravity currents and related phenomena. J. Fluid Mech., 31(2), 209248.
Étienne, J., Saramito, P. and Hopfinger, E.J.. 2004. Numerical simulations of dense clouds on steep slopes: application to powder-snow avalanches. Ann. Glaciol., 38, 379383.
Fukushima, Y. and Parker, G.. 1990. Numerical simulation of powder-snow avalanches. J. Glaciol., 36(123), 229237.
Grigoryan, S.S., Urumbayev, N.A. and Nekrasov, I.V.. 1982. Experimental’noye issledovaniye lavinnoy vozdushnoy volny [Experimental studies of an avalanche wind]. Mater. Glyatsiol. Issled./Data Glaciol. Stud. 44, 8794.
Harris, T.C., Hogg, A.J. and Huppert, H.E.. 2002. Polydisperse particle-driven gravity currents. J. Fluid Mech., 472, 333371.
Hogg, A.J. and Woods, A.W.. 2001. The transition from inertiato bottom-drag-dominated motion of turbulent gravity currents. J. Fluid Mech., 449, 201224.
Landau, L.D. and Lifshitz, E.M.. 1987. Fluid mechanics. Second edition. Oxford, Butterworth-Heinemann. (Course in Theoretical Physics 6.)
McElwaine, J.N. 2002. Image analysis for avalanches. In Naaim, M. and Naaim-Bouvet, F., eds. Proceedings of the International Seminar on Snow and Avalanche Test Sites, 22–23 November 2001, Grenoble, France. Antony (Hauts-de-Seine), Cemagref éditions, 411428.
McElwaine, J.N. 2005. Rotational flow in gravity current heads. Philos. Trans. R. Soc. London, Ser. A, 363(1832), 16031623.
McElwaine, J.N. and Nishimura, K.. 2001. Ping-pong ball avalanche experiments. In McCaffrey, W.D., Kneller, B.C. and Peakall, J., eds. Particulate gavity currents. Chichester, Blackwell Science, 135148. (International Association of Sedimentologists Special Publication 31.)
McElwaine, J.N. and Turnbull, B.. 2005. Air pressure data from the Valle de la Sionne avalanches of 2004. J. Geophys. Res., 110(F3), F03010. (10.1029/2004JF000237.)
Nishimura, K., Narita, H., Maeno, N. and Kawada, K.. 1989. The internal structure of powder-snow avalanches. Ann. Glaciol., 13, 207210.
Nohguchi, Y. and Ozawa, H.. 2009. On the vortex formation at the moving front of lightweight granular particles. Physica D, 238(1), 2026.
Simpson, J.E. 1997. Gravity currents in the environment and in the laboratory. Second edition. Cambridge, etc., Cambridge University Press.
Turnbull, B. and McElwaine, J.N.. 2008. Experiments on the non-Boussinesq flow of self-igniting suspension currents on a steep open slope. J. Geophys. Res., 113(F1), F01003. (10.1029/2007JF000753.)
Turnbull, B., McElwaine, J.N. and Ancey, C.. 2007. The Kulikovskiy–Sveshnikova–Beghin model of powder snow avalanches: development and application. J. Geophys. Res., 112(F1), F01004. (10.1029/2006JF000489.)
Turner, J.S. 1973. Buoyancy effects in fluids. Cambridge, etc., Cambridge University Press.
Von Kármán, T. 1940. The engineer grapples with non-linear problems. Bull. Am. Math. Soc., 46, 615683.

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Potential flow models of suspension current air pressure

  • Barbara Turnbull (a1) and Jim N. McElwaine (a2)

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