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Examination of stochastic dispersion theory by MRI in aperiodic porous media
Author(s) -
Irwin N. C.,
Greenkorn R. A.,
Altobelli S. A.,
Cushman J. H.
Publication year - 2000
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690461203
Subject(s) - aperiodic graph , covariance , perturbation theory (quantum mechanics) , second moment of area , statistical physics , porous medium , mathematics , moment (physics) , covariance matrix , covariance function , perturbation (astronomy) , mathematical analysis , physics , mechanics , porosity , thermodynamics , statistics , chemistry , classical mechanics , quantum mechanics , organic chemistry , combinatorics
Magnetic resonance imaging techniques were applied to obtain concentration and velocity field measurements during flow in an aperiodic heterogeneous porous medium. These measurements were used to evaluate the applicability of a stochastic perturbation theory and the validity of the assumptions underlying its derivation. A comparison of experimental moment data to the first and second moments of simulated mean concentration distributions showed that the theory did not match the experimental data. While the results showed general agreement, the stochastic model appeared to slightly overpredict the experimentally observed mixing behavior. Discrepancies between experimental and numerical results were attributed to the assumption that triplet correlation terms involving fluctuating velocities and fluctuating concentration are insignificant relative to terms containing doublet cross‐correlations. Measured velocity covariances were compared to the velocity covariance determined from the first‐order solution to the flow equation. The first‐order relation agreed generally with the measured covariance, but did not accurately predict the detailed covariance structure in the aperiodic heterogeneous model.