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Upscaling unsaturated flow in binary porous media with air entry pressure effects
Author(s) -
Szymkiewicz Adam,
Helmig Rainer,
Neuweiler Insa
Publication year - 2012
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2011wr010893
Subject(s) - porous medium , capillary pressure , imbibition , capillary action , mechanics , relative permeability , richards equation , flow (mathematics) , porosity , permeability (electromagnetism) , geotechnical engineering , airflow , materials science , air permeability specific surface , two phase flow , geology , thermodynamics , chemistry , composite material , physics , water content , biochemistry , botany , germination , layer (electronics) , membrane , biology
We consider flow in a porous medium containing coarse‐textured inclusions with a low value of air entry pressure, embedded in a fine‐textured background material having high entry pressure. During imbibition some air remains trapped in the inclusions, while during drainage the inclusions become drained only after the capillary entry pressure exceeds the pressure of the background material. These effects can only be reproduced by a two‐phase flow model, and not by the Richards' equation. However, if an upscaled form of the Richards' equation with appropriately modified capillary and permeability functions is used, the results are in a reasonable agreement with the two‐phase flow model.