Unsaturated flow in a centrifugal field: Measurement of hydraulic conductivity and testing of Darcy's Law

Water Resources Research
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Abstract

A method has been developed to establish steady state flow of water in an unsaturated soil sample spinning in a centrifuge. Theoretical analysis predicts moisture conditions in the sample that depend strongly on soil type and certain operating parameters. For Oakley sand, measurements of flux, water content, and matric potential during and after centrifugation verify that steady state flow can be achieved. Experiments have confirmed the theoretical prediction of a nearly uniform moisture distribution for this medium and have demonstrated that the flow can be effectively one-dimensional. The method was used for steady state measurements of hydraulic conductivity K for relatively dry soil, giving values as low as 7.6 × 10−11 m/s with data obtained in a few hours. Darcy's law was tested by measuring K for different centrifugal driving forces but with the same water content. For the sand at a bulk density of 1.82 Mg/m3 and 27% saturation, results were consistent with Darcy's law for K equal to 5.22 × 10−10 m/s and forces ranging from 216 to 1650 times normal gravity.

Publication type Article
Publication Subtype Journal Article
Title Unsaturated flow in a centrifugal field: Measurement of hydraulic conductivity and testing of Darcy's Law
Series title Water Resources Research
DOI 10.1029/WR023i001p00124
Volume 23
Issue 1
Year Published 1987
Language English
Publisher American Geophysical Union
Contributing office(s) Toxic Substances Hydrology Program
Description 11 p.
First page 124
Last page 134
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