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Water Vapor Movement in Soil: Reconciliation of Theory and Experiment
Author(s) -
Jury W. A.,
Letey J.
Publication year - 1979
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1979.03615995004300050001x
Subject(s) - water vapor , phenomenological model , thermodynamics , saturation (graph theory) , range (aeronautics) , movement (music) , flux (metallurgy) , water content , chemistry , physics , mathematics , materials science , geology , organic chemistry , geotechnical engineering , condensed matter physics , acoustics , combinatorics , composite material
A large number of separate experimental studies of water vapor movement in response to thermal gradients are shown to be independent of water content over a wide range of water contents. Two models, proposed by J. R. Philip and D. A. de Vries (1957) and J. W. Cary (1963), are rewritten in a compatible form and compared to the data. The phenomenological model of Cary describes the data if the phenomenological coefficient β has a value between 1.0 and 3.5, whereas the mechanistic theory of Philip and de Vries underpredicts the vapor transport observed in the experiments in all cases. A modification of the theory of Philip and de Vries is proposed which increases the influence of liquid water on vapor transport. In the new formulation the experimental information is adequately described and both models are rendered compatible. Both experimental and theoretical results suggest that water vapor movement may be described by a simple expression which is a known function of temperature, and is independent of water content over a wide range of saturation. Even without calibration it is suggested that this expression can describe water vapor flux to within a factor of 2.