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The influence of the form of the log‐conductivity covariance on non‐Fickian dispersion in random permeability fields
Author(s) -
Salandin Paolo,
Rinaldo Andrea
Publication year - 1989
Publication title -
international journal for numerical methods in engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.421
H-Index - 168
eISSN - 1097-0207
pISSN - 0029-5981
DOI - 10.1002/nme.1620270115
Subject(s) - covariance , hydraulic conductivity , dispersion (optics) , porous medium , permeability (electromagnetism) , statistical physics , exponential function , random field , soil science , groundwater , covariance function , mathematics , mechanics , statistics , environmental science , geotechnical engineering , physics , mathematical analysis , porosity , chemistry , engineering , optics , biochemistry , membrane , soil water
The paper deals with non‐Fickian dispersion of inert solutes in random permeability fields. Attention is focused critically on the statistical characterization of the porous medium which affects pollutant dispersion in groundwater. After a brief account of recent results of stochastic theories of transport in porous media and of the fundamental indications of large‐scale field experiments, it is inferred from numerical studies that the particular choice of an analytical form of covariance of log‐conductivity has a poor influence on the overall dispersion process. In fact, different covariance structures with the same macroscale (a measure of the distance between two points beyond which the permeability ceases to be correlated) yield very similar dispersion processes. The result has a noteworthy bearing on field studies of pollutant dispersion in groundwater because it underlines the reliability of exponential correlation structures yielding analytical expression for time‐varying macrodispersion coefficients.