 |
| Titel |
Averaging hydraulic head, pressure head, and gravitational head in subsurface hydrology, and implications for averaged fluxes, and hydraulic conductivity |
| VerfasserIn |
G. H. Rooij |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 13, no. 7 ; Nr. 13, no. 7 (2009-07-13), S.1123-1132 |
| Datensatznummer |
250011935
|
| Publikation (Nr.) |
 copernicus.org/hess-13-1123-2009.pdf |
|
|
|
|
|
| Zusammenfassung |
| Current theories for water flow in porous media are valid for scales much
smaller than those at which problem of public interest manifest themselves.
This provides a drive for upscaled flow equations with their associated
upscaled parameters. Upscaling is often achieved through volume averaging,
but the solution to the resulting closure problem imposes severe
restrictions to the flow conditions that limit the practical applicability.
Here, the derivation of a closed expression of the effective hydraulic
conductivity is forfeited to circumvent the closure problem. Thus, more
limited but practical results can be derived. At the Representative
Elementary Volume scale and larger scales, the gravitational potential and
fluid pressure are treated as additive potentials. The necessary requirement
that the superposition be maintained across scales is combined with
conservation of energy during volume integration to establish consistent
upscaling equations for the various heads. The power of these upscaling
equations is demonstrated by the derivation of upscaled water content-matric
head relationships and the resolution of an apparent paradox reported in the
literature that is shown to have arisen from a violation of the
superposition principle. Applying the upscaling procedure to Darcy's Law
leads to the general definition of an upscaled hydraulic conductivity. By
examining this definition in detail for porous media with different degrees
of heterogeneity, a series of criteria is derived that must be satisfied for
Darcy's Law to remain valid at a larger scale. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|