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| Titel |
Mixing Dynamics and Flow Topology in Heterogeneous Porous Media |
| VerfasserIn |
Marco Dentz, Tanguy Le Borgne, Felipe P. J. de Barros |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250099559
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| Publikation (Nr.) |
 EGU/EGU2014-15355.pdf |
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| Zusammenfassung |
| We study the mixing behavior of a dissolved substance in a Darcy scale heterogeneous porous
medium. Flow heterogeneity is induced by spatially variable hydraulic conductivity. The
fundamental mechanism governing the mixing dynamics are the competition of stretching
and compression of a material element as well as local shear on one hand, and diffusion on
the other. In order to quantify these mechanisms and relate them to the flow heterogeneity, we
study the evolution of a solute that evolves from an initial distribution that is small
compared to the characteristic heterogeneity scale. Our focus is to investigate how
the kinematical and topological properties of the flow field enhance mixing of the
solute cloud with the surrounding fluid. To this end, we formulate the transport
problem in a Lagrangian framework and relate the particle dynamics explicitly to the
Lagrangian deformation of fluid elements, and thus to the topology of the flow field. For
high Peclet numbers, the solute evolution can be characterized by the time series
of Lagrangian stretching and shear rates in the coordinate system of the material
element. These processes are quantified by stochastic evolution equations, and
linked to the topology of the flow field. We derive a predictive framework for the
evolution of mixing, and evaluate the mixing efficiency for different flow topologies. |
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