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| Titel |
Infiltrative instability near topography with implication for the drainage of soluble rocks |
| VerfasserIn |
P. Genthon, A. Ormond |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 12, no. 6 ; Nr. 12, no. 6 (2008-12-01), S.1285-1293 |
| Datensatznummer |
250010957
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| Publikation (Nr.) |
 copernicus.org/hess-12-1285-2008.pdf |
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| Zusammenfassung |
| We present here numerical modeling of infiltration instability near a
topographic edge of a water-saturated porous slice by analogy with a
limestone formation devoid of initial heterogeneities such as fractures
faults or joints and limited by a vertical cliff. In our runs a first
dissolution finger develops near the cliff edge, and ends to intersect it
above its mid height. Additional fingers develop upstream with a decreasing
growth rate and an increasing width. This results from the decrease of the
infiltration velocity with distance to the cliff in our models. A
sensitivity study shows that a larger permeability contrast between the
fingers and the initial undissolved porous medium produces a larger number
of fingers, while increasing the dispersivity (lower Peclet number) produces
wider fingers. A slower reaction rate (lower Damkhöler number) produces
fingers that follow the initial flow lines, since dissolution occurs
simultaneously along the entire finger. These results suggest that
alteration by dissolution of limestones or other soluble formations may
produce different underground channel structures in the same drainage basin
due to local changes of the non-dimensional Pe and Da numbers. |
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