OATAO - Open Archive Toulouse Archive Ouverte Open Access Week

Analysis of the impact of surface layer properties on evaporation from porous systems using column experiments and modified definition of characteristic length

Assouline, Shmuel and Narkis, Kfir and Gherabli, Rivka and Lefort, Philippe and Prat, Marc Analysis of the impact of surface layer properties on evaporation from porous systems using column experiments and modified definition of characteristic length. (2014) Water Resources Research, 50 (4). 1-22. ISSN 0043-1397

[img]
Preview
(Document in English)

PDF (Author's version) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
1MB

Official URL: http://dx.doi.org/10.1002/2013WR014489

Abstract

The hydraulic properties of the layer at the vicinity of the soil surface have significant impact on evaporation, and could be harnessed to reduce water losses. The effect of the properties of the upper layer on the evolution of phase distribution during the evaporation process is first illustrated from three-dimensional pore network simulations. This effect is then studied from experiments carried out on soil columns under laboratory conditions. Comparisons between homogeneous columns packed with coarse (sand) and fine (sandy loam) materials, and heterogeneous columns packed with layers of fine overlying coarse material and coarse overlying fine material of different thicknesses are performed to assess the impact of upper layer properties on evaporation. Experiments are analyzed using the classical approach based on the numerical solution of Richards’s equation and semi-analytical theoretical predictions. The theoretical analysis is based on the clear distinction between two drying regimes, namely the capillary regime and the gravity-capillary regime, which are the prevailing regimes in our experiments. Simple relationships enabling to estimate the duration of stage-1 evaporation (S1) for both regimes are proposed. In particular, this led to defining the characteristic length for the gravity-capillary regime from the consideration of viscous effects at low water content differently from available expressions. The duration of S1, during which most of the water losses occur, for both the homogeneous and two-layer columns are presented and discussed. Finally, the impact of liquid films and it consequences on the soil hydraulic conductivity function are briefly discussed.

Item Type:Article
Additional Information:Thanks to AGU editor. The original publication is available at http://onlinelibrary.wiley.com
HAL Id:hal-01002258
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Other partners > Agricultural Research Organization - ARO (ISRAEL)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Laboratory name:
Statistics:download
Deposited By: Marc PRAT
Deposited On:05 Jun 2014 16:07

Repository Staff Only: item control page