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| Titel |
Impact of mixing interface dynamics on concentration distributions in heterogeneous porous media |
| VerfasserIn |
Tanguy Le Borgne, Marco Dentz, Emmanuel Villermaux |
| 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 |
250098387
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| Publikation (Nr.) |
 EGU/EGU2014-14058.pdf |
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| Zusammenfassung |
| The dynamics of mixing interfaces control a range of important subsurface processes,
including reactive transport, heat transfer, dispersion in multiphase flows, or chemical
elements cycling in streams and catchments. Mass transfer and chemical reactions
across these interfaces is expected to be strongly affected by their elongation and
folding resulting from the spatial and temporal fluctuations of flow velocities in the
subsurface. We propose a new modeling framework to quantify the impact of mixing
interface dynamics on the concentration distribution, predicting its shape and rate of
deformation as it progresses towards uniformity in the medium (Le Borgne et al., PRL,
2013).
The concentration field is represented by a set of stretched lamellae whose rate of
diffusive smoothing is locally enhanced by kinematic stretching. Based on the interplay
between stretching, diffusion and aggregation, we derive analytical expressions for the
concentration distribution, holding for all field heterogeneities, residence times, and Peclet
numbers. The theory provides predictions of the temporal evolution of concentration
moments, scalar dissipation rate and other mixing measures, quantifying the controls of
structural heterogeneities on the dynamics of mixing interfaces and the associated
concentration distributions. |
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