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| Titel |
Stability of haline density-driven flows in saturated heterogeneous media |
| VerfasserIn |
Jude Musuuza, Sabine Attinger, Florin Radu |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250040014
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| Zusammenfassung |
| Density-driven flows occur in deep aquifers due to temperature differences and
in coastal aquifers and refuse dumps due to solute concentration differences. Its
relevance cuts across many practical applications like (normal and nuclear) waste
repository management, exploitation of geothermal energy resources, enhanced oil
recovery from aquifers and remediation of contaminated sites. A typical feature of
density dependent flow problems is that they can become unstable (physically or
numerically).
A big challenge has been the absence of a general criterion that states whether flow is
physically stable or unstable and the optimum computational grid resolution needed to solve
the problem without creating numerical (artificial) instabilities. The homogenization theory
ideas from [1] were extended in [2] to derive a stability criterion for density-driven flows in
saturated homogeneous porous media. The criterion included the effects of density, viscosity
and velocity but could not adequately predict the onset of fingering when velocity was
varied.
That study is extended here to include dispersive and medium heterogeneity effects. The
specific objective is to answer the question: under what conditions do heterogeneities
stabilise or destabilise flow? The homogenization theory ideas from [1] are again used to
derive expressions for the elements of the macrodispersion tensor for flow aligned parallel to
gravity. The dependency of the temporal evolution of the coefficients on the density contrast,
heterogeneity variance, transverse dispersivity, anisotropy and correlation length are then
investigated and the results checked against numerical simulations performed with the
software toolbox d3 f.
The work will be extended to include temperature effects and it is hoped that the ideas can
be extended to flow in unsaturated soils.
REFERENCES
[1]Held, R., S. Attinger, and W. Kinzelbach (2005), Homogenization and effective parameters
for the Henry problem in heterogeneous formations, Water Resour. Res., 41, W11420,
doi:10.1029/2004WR003674.
[2]Musuuza J. L., S. Attinger, and F. A. Radu (2009), An extended stability criterion
for density-driven flows in homogeneous porous media, Advances in Water Resour., 32,
doi:doi:10.1016/j.advwatres.2009.01.012.
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