Solute dispersion for stable density-driven flow in randomly heterogeneous porous media
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Guadagnini&Riva-Dell_Oca_et_al ...
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Final Accepted Manuscript
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Univ Arizona, Dept Hydrol & Atmospher SciIssue Date
2018-01
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ELSEVIER SCI LTDCitation
Dell’Oca, A., M. Riva, J. Carrera, and A. Guadagnini (2018), Solute dispersion for stable density-driven flow in randomly heterogeneous porous media, Adv. Water Resour., 111, 329-345, doi:https://doi.org/10.1016/j.advwatres.2017.10.040Journal
ADVANCES IN WATER RESOURCESRights
© 2017 Elsevier Ltd. All rights reserved.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
We present a theoretical investigation on the processes underpinning the reduced longitudinal spreading documented in stable variable density flows, as opposed to constant density settings, within heterogeneous porous media. We do so by decomposing velocity and pressure in terms of stationary and dynamic components. The former corresponds to the solution of the constant density flow problem, while the latter accounts for the effects induced by density variability. We focus on a stable flow configuration and analyze the longitudinal spread of saltwater injected from the bottom of a column formed by a heterogeneous porous medium initially fully saturated by freshwater. We adopt a perturbation expansion approach and derive the equations satisfied by section-averaged concentrations and their ensemble mean values. These formulations are respectively characterized by a single realization and an ensemble dispersive flux, which we determine through appropriate closure equations. The latter are solved via semi-analytical and numerical approaches. Our formulations and associated results enable us to discriminate the relative impact on the density-driven solute displacement of (a) covariance of the permeability of the porous medium, (b) cross-covariance between permeability and concentration, which is in turn linked to the coupling of flow and transport problems, and (c) cross-covariance between the dynamic and stationary velocities.Note
24 month embargo; published online: 1 November 2017ISSN
03091708Version
Final accepted manuscriptSponsors
MIUR (Italian ministry of Education, University and Research); CICYT (Project MEDISTRAES)Additional Links
https://linkinghub.elsevier.com/retrieve/pii/S0309170817303329ae974a485f413a2113503eed53cd6c53
10.1016/j.advwatres.2017.10.040