Call number:
ZSP-202-296
In:
Research report
Description / Table of Contents:
A theory is developed to describe the percolation of water through isothermal snow with a vertical porosity gradient. While the necessary laboratory experiments have not been done for snow, concepts from the general theory of two phase flow through porous media are used in the development. The general solution for the one-dimensional problem is given, which, when combined with any periodic boundary condition, can be used to make quantitative predictions. The theory is applied to water percolation through firn on the upper Seward Glacier (Sharp, 1951a). Using appropriate values for the parameters, theory shows a wave of volume flux which travels down into the firn and develops features similar to those observed by Sharp. These include an initially symmetric wave which distorts with depth, continuous (rather than intermittent) downward flow beneath the surface, and a decreasing value for the wave crest with depth. The rate at which the waves propagate is calculated using the method of characteristics and is in fair agreement with the observed rate where the permeability of the bulk firn with ice layers is reduced by a factor of two over homogeneous snow samples studied in the laboratory (Kuroiwa, 1963). The theory predicts that the waves advance with a shock front which grows with depth. The shock front is thought to be only an approximation to the actual physical process
Description / Table of Contents:
CONTENTS: Preface. - Symbols. - Introduction. - Theory. - Darcy's Law. - Functional permeability. - Equations. - Characteristics. - Seward Glacier firn. - Discussion. - Summary. - Literature cited. - Abstract.
Type of Medium:
Series available for loan
Pages:
iv, 17 Seiten
,
Illustrationen
Series Statement:
Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 296
URL:
http://www.worldcat.org/oclc/1035634529
Language:
English
Branch Library:
AWI Library
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