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The quasilinear approximation for unsaturated porous media flow
Author(s) -
Pullan A. J.
Publication year - 1990
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/wr026i006p01219
Subject(s) - richards equation , porous medium , exponential function , flow (mathematics) , nonlinear system , hydraulic conductivity , linear approximation , vadose zone , mathematics , moisture , geotechnical engineering , mechanics , mathematical analysis , water content , porosity , geology , soil science , physics , meteorology , soil water , groundwater , quantum mechanics
This paper gives a review of the quasilinear approximation, an exponential relationship between hydraulic conductivity and moisture potential, and the uses this has been put to since the time of its creation. One of the major attractions of this approximation is that under steady regimes the highly nonlinear Richards equation governing unsaturated flow can be linearized. This simplification has enabled analytic and semianalytic solutions to be found for many unsaturated flow problems. These are reviewed, and the current research areas, in which the quasilinear approximation is being used, are discussed.