Vortices of Electro-osmotic Flow in Heterogeneous Porous Media

Traditional models of electrokinetic transport in porous media are based on homogenized material properties, which neglect any macroscopic effects of microscopic fluctuations. This perspective is taken not only for convenience, but also motivated by the expectation of irrotational electro-osmotic fl...

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Bibliographic Details
Published inarXiv.org
Main Authors Mirzadeh, Mohammad, Zhou, Tingtao, Mohammad Amin Amooie, Fraggedakis, Dimitrios, Ferguson, Todd R, Bazant, Martin Z
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 12.03.2020
Subjects
Charging
Computational fluid dynamics
Electric fields
Electrokinetics
Electroosmosis
Fluid flow
Heterogeneity
Material properties
Physics - Fluid Dynamics
Porous media
Surface charge
Thin films
Vortices
Zeta potential
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Summary:Traditional models of electrokinetic transport in porous media are based on homogenized material properties, which neglect any macroscopic effects of microscopic fluctuations. This perspective is taken not only for convenience, but also motivated by the expectation of irrotational electro-osmotic flow, proportional to the electric field, for uniformly charged surfaces (or constant zeta potential) in the limit of thin double layers. Here, we show that the inherent heterogeneity of porous media generally leads to macroscopic vortex patterns, which have important implications for convective transport and mixing. These vortical flows originate due to competition between pressure-driven and electro-osmotic flows, and their size are characterized by the correlation length of heterogeneity in permeability or surface charge. The appearance of vortices is controlled by a single dimensionless control parameter, defined as the ratio of a typical electro-osmotic velocity to the total mean velocity.
ISSN:2331-8422
DOI:10.48550/arxiv.2003.05974