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Solute Dispersion During Axisymmetric Three‐Dimensional Unsaturated Water Flow
Author(s) -
Clothier B. E.,
Elrick D. E.
Publication year - 1985
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1985.03615995004900030004x
Subject(s) - streamlines, streaklines, and pathlines , mechanics , infiltration (hvac) , rotational symmetry , point source , flux (metallurgy) , dispersion (optics) , front (military) , vadose zone , geology , geometry , physics , geotechnical engineering , thermodynamics , chemistry , groundwater , mathematics , optics , meteorology , organic chemistry
Abstract An approximate, analytic solution is presented for the smearing of solute by both convection and dispersion during axisymmetric three‐dimensional constant flux infiltration from a surface point source in unsaturated soil. The steady‐state pattern of axisymmetric streamlines is used to track individual parcels of water as they move away from the surface emitter. A simple analytic expression is developed to describe the time course of the hydrodynamic dispersion of solute about the convected front as it moves along any given streamline. The location of the convected front at any time is predicted from the profile of wetting along that streamline. The plane‐of‐separation concept is used to find the distance travelled by the convected front along the streamline. The invading solution is considered to act as if to effectively piston‐displace the antecedent soil water. Profiles of bromide concentration along three streamline paths were measured during constant‐flux point‐source infiltration experiments in the laboratory with fine sand. These measurements compared favorably with the theoretical predictions.