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Poster communications

Continuous Time Random Walks and the Causes of Non-Fickian Transport in Heterogeneous Media

Abstract : Solute transport in heterogeneous porous media is in general non-Fickian, this means it shows behaviors that do not conform to advection-dispersion models characterized by constant equivalent transport parameters. The causes for such behaviors are manifold, while their quantitative relation to large scale non-Fickian transport is often not known. We address the questions of (i) how different heterogeneity and microscale transport mechanisms manifest in large scale transport behavior, (ii) which are their impacts on anomalous solute dispersion, and (iii) how they can be quantified in terms of large scale dynamics. We focus here on the roles of medium and flow heterogeneity, mass transfer between mobile and immobile zones, as well as spatially variable retardation properties on large scale anomalous transport. Starting from the different microscale heterogeneity and transport dynamics, we use a stochastic modeling approach to coarse grain and average particle transport in a Lagrangian modeling framework, and quantify the large scale particle dynamics in terms of continuous time random walks (CTRW). The large scale particle movements are characterized in terms of a random space increment, which can be related to the heterogeneity structure and geometry, and a random time increment, which is quantified in terms of the heterogeneity distribution. We present the CTRW models resulting from the different heterogeneity scenarios and analyze their transport signatures in terms of solute dispersion and breakthrough curves.
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Poster communications
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https://hal-insu.archives-ouvertes.fr/insu-01241928
Contributor : Isabelle Dubigeon <>
Submitted on : Friday, December 11, 2015 - 11:07:14 AM
Last modification on : Wednesday, August 7, 2019 - 11:44:06 AM

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  • HAL Id : insu-01241928, version 1

Citation

Marco Dentz, Tanguy Le Borgne, Peter Kang. Continuous Time Random Walks and the Causes of Non-Fickian Transport in Heterogeneous Media . AGU Fall Meeting 2015, Dec 2015, San Francisco, United States. pp.H31B-1410, 2015. ⟨insu-01241928⟩

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