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Reference Category Journals
DOI 10.1007/s12665-013-2420-1
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Title (Primary) A coupled surface/subsurface flow model accounting for air entrapment and air pressure counterflow
Author Delfs, J.-O.; Wang, W. ORCID logo ; Kalbacher, T.; Singh, A.K.; Kolditz, O. ORCID logo
Source Titel Environmental Earth Sciences
Year 2013
Department ENVINF
Volume 69
Issue 2
Page From 395
Page To 414
Language englisch
Keywords Coupled flow; Two-phase flow; Horton runoff; Leakance; Soil gas release; OpenGeoSys (OGS)
UFZ wide themes RU5;
Abstract This work introduces the soil air system into integrated hydrology by simulating the flow processes and interactions of surface runoff, soil moisture and air in the shallow subsurface. The numerical model is formulated as a coupled system of partial differential equations for hydrostatic (diffusive wave) shallow flow and two-phase flow in a porous medium. The simultaneous mass transfer between the soil, overland, and atmosphere compartments is achieved by upgrading a fully established leakance concept for overland-soil liquid exchange to an air exchange flux between soil and atmosphere. In a new algorithm, leakances operate as a valve for gas pressure in a liquid-covered porous medium facilitating the simulation of air out-break events through the land surface. General criteria are stated to guarantee stability in a sequential iterative coupling algorithm and, in addition, for leakances to control the mass exchange between compartments. A benchmark test, which is based on a classic experimental data set on infiltration excess (Horton) overland flow, identified a feedback mechanism between surface runoff and soil air pressures. Our study suggests that air compression in soils amplifies surface runoff during high precipitation at specific sites, particularly in near-stream areas.
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Delfs, J.-O., Wang, W., Kalbacher, T., Singh, A.K., Kolditz, O. (2013):
A coupled surface/subsurface flow model accounting for air entrapment and air pressure counterflow
Environ. Earth Sci. 69 (2), 395 - 414 10.1007/s12665-013-2420-1