Basal-flow characteristics of a non-linear flow sliding frictionless over strongly undulating bedrock

Gudmundsson, Hilmar (1997) Basal-flow characteristics of a non-linear flow sliding frictionless over strongly undulating bedrock. Journal of Glaciology, 43 (143). pp. 80-89. ISSN 0022-1430

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Abstract

The flow field of a medium sliding without friction over a strongly undulating surface is calculated numerically. The results are used to elucidate the basal-flow characteristics of glacier flow and they are discussed with reference to known analytical solutions. Extrusion flow is found to become increasingly pronounced as the value of n, where n is a parameter in Glen’s flow law, becomes larger. For sinusoidal bedrock undulations, a flow separation occurs if the amplitude-to-wavelength ratio exceeds a critical value of about 0.28. The main flow then sets up a secondary flow circulation within the trough, and the ice participating in this circular motion theoretically never leaves it. The sliding velocity is calculated numerically as a function of the mean basal shear stress, the amplitude-to-wavelength ratio and the flow parameter n. For moderate and high slope fluctuations, the sliding velocity is significantly different from what would be expected from results based on the small-slope approximation.

Item Type:	Article
Subjects:	F800 Physical and Terrestrial Geographical and Environmental Sciences
Department:	Faculties > Engineering and Environment > Geography and Environmental Sciences
Depositing User:	Becky Skoyles
Date Deposited:	20 Feb 2019 16:18
Last Modified:	10 Oct 2019 23:30
URI:	http://nrl.northumbria.ac.uk/id/eprint/38145

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