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Infiltration from a surface point source and drip irrigation: 2. An approximate time‐dependent solution for wet‐front position
Author(s) -
Revol P.,
Clothier B. E.,
Mailhol J.C.,
Vachaud G.,
Vauclin M.
Publication year - 1997
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 - 10.1029/97wr01007
Subject(s) - streamlines, streaklines, and pathlines , infiltration (hvac) , point source , mechanics , capillary action , transient flow , mathematics , steady state (chemistry) , physics , meteorology , chemistry , optics
Raats ' [1971] steady state theory is here extended to provide an approximate analysis of the transient pattern of wetting around a point source. The assumption that a steady state regime prevails behind the wet front and the use of the Clothier [1984] and Philip [1984] theories on water movement along the streamlines allows an approximate transient solution for surface point source infiltration to be developed. This procedure was previously tested against absorption theory and laboratory experiments [ Revol et al ., 1995], but now this new analysis is evaluated via a field test. The vertical elongating influence of gravity is found to be well predicted. Application of this analysis to design purposes is also mentioned. The role of the macroscopic characteristic capillary length of unsaturated flow, λ c , is highlighted by this approximate solution. Finally, we propose a method that allows estimation of λ c from a point‐source infiltration experiment.