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The Prediction of Partial Anaerobiosis in Saturated Soil: A Transient Moving Boundary Problem
Author(s) -
McConnaughey P. K.,
Bouldin D. R.
Publication year - 1984
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/sssaj1984.03615995004800050004x
Subject(s) - transient (computer programming) , steady state (chemistry) , boundary (topology) , dimensionless quantity , mathematics , mechanics , boundary value problem , transient state , mathematical analysis , physics , chemistry , computer science , engineering , electrical engineering , operating system
Past models of partial anaerobiosis in saturated aggregates or thin layers of sediment have assumed steady‐state conditions. In this paper, the transient case in one dimension is described. A numerical boundary‐tracking technique was derived to solve the transient case, and a “quasi‐steady‐state” approximate solution was presented. The numerical method yielded accurate results for two test problems, and was shown to converge as the computational mesh was refined. A dimensionless transient problem was solved and the transient numerical solution and a “quasi‐steady‐state” approximation yielded similar results for aerobic/anaerobic boundary velocities < 7 × 10 −3 m d −1 . This boundary velocity is much greater than those noted in the literature. The results demonstrate that the quasi‐steady‐state approximation is an acceptable description of aerobic/anaerobic boundary movement and oxygen consumption rates under most soil conditions.