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Asymptotic profiles of a decaying contaminant in transport through a porous medium

Published online by Cambridge University Press:  26 September 2008

M. Escobedo
Affiliation:
Department of Mathematics, Universidad del Pais Vasco, Bilbao, Spain
R. E. Grundy
Affiliation:
Department of Mathematical and Computational Sciences, University of St Andrews, Scotland

Abstract

In this paper we construct formal large-time solutions of a model equation, with initial data possessing bounded support, describing transport of a reacting and decaying contaminant in a porous medium. This we do in one, two and three space dimensions where, depending on the reaction model used, the solution may or may not have bounded support for all time. In the former case, working with what we call the reduced equation, we prove convergence, in one space dimension, to an outer limit as t → ∞. The outer solution has to be supplemented by inner solutions valid near the edges of the support. These inner solutions take the form of decaying travelling waves which we analyse using phase plane methods. Using the travelling waves as sub- and super-solutions, we establish the large-time behaviour of the interfaces which we refine using asymptotic matching. These ideas can be formally extended to higher space dimensions where we deduce the shape of the support of the large-time profiles which turns out to be ellipsoidal. For reaction models where the support is unbounded we prove convergence of the solution of the reduced equation to a travelling and decaying fundamental solution of the linear heat equation with convection and absorption. Finally, we indicate how the results for the reduced equations can be formally embedded in an asymptotic analysis of the original model equation.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1996

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References

Aronson, D. G. (1980) Density-Dependent Interactive-Diffusion Systems: Dynamics and Modelling of Reactive Systems. Academic Press.Google Scholar
Bertsch, M., Kersner, R. & Peletier, L. A. (1982) Sur le comportement de la frontiere dans une equation en theorie de la filtration. C. R. Acad. Sc. Paris, t. 295.Google Scholar
Boesten, J. J. T. I. (1987) Behaviour of herbicides in soil: simulation and experimental assessment. Ph.D. Thesis, Institute of Pesticide Research, Wageningen.Google Scholar
Bolt, G. H. (1979) Soil Chemistry B. Physico-Chemical Models. Elsevier.Google Scholar
Caffarelli, L. A., Vazquez, J. L. & Wolanski, N. I. (1987) Lipschitz continuity of solutions and interfaces of the N-dimensional porous medium equation. Indiana Univ. Math. J. 3, 373401.CrossRefGoogle Scholar
Dagan, G. (1989) Flow and Transport in Porous Formations. Springer-Verlag.CrossRefGoogle Scholar
De Josselin de Jong, G. (1958) Longitudinal and transverse diffusion in granular deposits. Trans. Amer. Geophys. Union 39, 6774.Google Scholar
Dawson, C. N., van Duijn, C. J. & Grundy, R. E. (1996) SIAM J. Applied Maths (accepted).Google Scholar
DiBenedetto, E. (1983) Continuity of weak solutions to a general porous media equation. Indiana Univ. Math. J. 32, 83118.CrossRefGoogle Scholar
van Duijn, C. J., Grundy, R. E. & Dawson, C. N. (1995) Limiting profiles in reactive solute transport. Preprint.Google Scholar
Escobedo, M. & Zuazua, E. (1991) Large time behaviour of a convection diffusion equation in RN. J. Funct. Anal. 100, 119161.CrossRefGoogle Scholar
Grundy, R. E., van Duijn, C. J. & Dawson, C. N. (1994) Asymptotic profiles with finite mass in one dimensional contaminant transport through porous media: the fast reaction case. Quart. J. Mech. Appl. Math. 47, 69106.CrossRefGoogle Scholar
Kamin, S. & Peletier, L. A. (1986) Large time behaviour of solutions of the porous media equation with absorption. Israel J. Mathematics 55, 129146.CrossRefGoogle Scholar
Kamin, S., Peletier, L. A. & Vazquez, J. L. (1989) Classification of singular solutions of a nonlinear heat equation. Duke Math. J. 58(3), 601615.CrossRefGoogle Scholar
King, A. C. & Needham, D. J. (1994) The effects of variable diffusivity on the development of travelling waves in a class of reaction-diffusion equations. Phil. Trans. R. Soc. Lond. A 384, 229260.Google Scholar
Saffman, P. G. (1959) A theory of dispersion in porous media. J. Fluid Mech. 6(3), 321349.CrossRefGoogle Scholar
Saffman, P. G. (1960) Dispersion due to molecular diffusion and macroscopic mixing in flow through a network of capillaries. J. Fluid Mech. 7(2), 194208.CrossRefGoogle Scholar
Steinberg, S. M., Pignatello, J. J. & Sahney, B. L. (1987) Persistence of 1,2-Dibromoethane in soils: entrapment in intraparticle micropores. Environ. Sci. Technol. 21(12), 12011208.CrossRefGoogle Scholar