Laboratory investigation of longitudinal dispersion in anisotropic porous media

Water Resources Research
By: , and 

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Abstract

In this study, laboratory experiments were used to investigate mechanisms that may cause anisotropy in the dispersion coefficient and to investigate the relation between anisotropy in hydraulic conductivity and anisotropy in longitudinal dispersion. Measurements of sodium chloride concentration (used as a tracer) were made at 105 in situ sampling locations in a new type of sand box designed to allow flow in either of two perpendicular directions. Two types of hydraulic anisotropy were examined. The first consisted of structured zones of increased hydraulic conductivity within a lower-conductivity medium. The second type involved low-conductivity platelike inclusions within a homogeneous, isotropic medium. The plates were aligned such that the tortuosity was increased only in one principal direction of permeability. Results using two examples of the first type of media showed that the apparent longitudinal dispersivities for flow parallel to the high-conductivity direction were greater than those perpendicular to this direction. Two examples of the second type of media produced smaller apparent longitudinal dispersivities for flow parallel to the high-conductivity direction. The results suggest that the mechanisms causing dispersive anisotropy can be related, conceptually, to the factors causing hydraulic anisotropy.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Laboratory investigation of longitudinal dispersion in anisotropic porous media
Series title Water Resources Research
DOI 10.1029/WR023i011p02145
Volume 23
Issue 11
Year Published 1987
Language English
Publisher American Geophysical Union
Contributing office(s) Toxic Substances Hydrology Program
Description 7 p.
First page 2145
Last page 2151