Hostname: page-component-586b7cd67f-rdxmf Total loading time: 0 Render date: 2024-11-22T08:11:59.487Z Has data issue: false hasContentIssue false

Three dimensional similarity solutions of the nonlinear diffusion equation from optimization and first integrals

Published online by Cambridge University Press:  17 February 2009

J.-Y. Parlange
Affiliation:
School of Australian Environmental Studies, Griffith University, Nathan, Queensland 4111
R. D. Braddock
Affiliation:
School of Australian Environmental Studies, Griffith University, Nathan, Queensland 4111
G. Sander
Affiliation:
School of Australian Environmental Studies, Griffith University, Nathan, Queensland 4111
F. Stagnitti
Affiliation:
School of Australian Environmental Studies, Griffith University, Nathan, Queensland 4111
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

For diffusion problems, the boundary conditions are specified at two distinct points, yielding a two end-point boundary value problem which normally requires iterative techniques. For spherical geometry, it is possible to specify the boundary conditions at the same points, approximately, by using an optimization principle for arbitrary diffusivity. When the diffusivity obeys a power or an exponential law, a first integral exists and iteration can be avoided. For those two exact cases, it is shown that the general optimization result is extremely accurate when diffusivity increases rapidly with concentration.

Type
Research Article
Copyright
Copyright © Australian Mathematical Society 1982

References

[1]Anderson, N. and Arthurs, A. M., “Dual extremum principles for a nonlinear diffusion problem”, Quart. Appl. Math. 35 (1977), 188190.CrossRefGoogle Scholar
[2]Biggar, J. W. and Nielsen, D. R., “Spatial variability of the leaching characteristics of a field soil”, Water Resour. Res. 12 (1976), 7884.CrossRefGoogle Scholar
[3]Bruce, R. R. and Klute, A., “The measurement of soil-water diffusivity”, Soil Sci. Soc. Am. Proc. 20 (1956), 458462.CrossRefGoogle Scholar
[4]Crank, J., The mathematics of diffusion (Oxford University Press, 1st Edition, 1956, Chapter XI).Google Scholar
[5]Ince, E. L., Ordinary differential equations (Dover, 1st Edition, 1956, Chapter IV).Google Scholar
[6]Matano, C., “On the relation between the diffusion coefficients and concentration of solid materials (the nickel-copper system)”, Jap. J. Phys. 8 (1933), 109113.Google Scholar
[7]Parlange, J.-Y., “On solving the flow equation in unsaturated soils by optimization: horizontal infiltration”, Soil Sci. Soc. Am. Proc. 39 (1975), 415418.CrossRefGoogle Scholar
[8]Parlange, J.-Y., “Water transport in soils”, Ann. Rev. Fluid. Mech. 12 (1980), 77102.CrossRefGoogle Scholar
[9]Pert, G. J., “A class of similar solutions of the nonlinear diffusion equation”, J. Phys. A: Math. Gen. 10 (1977), 583593.CrossRefGoogle Scholar
[10]Reichardt, K., Neilsen, D. R. and Biggar, J. W., “Scaling of horizontal infiltration into homogeneous soils”, Soil Sci. Soc. Am. J. 36 (1977), 241245.CrossRefGoogle Scholar
[11]Sawhney, B. L. and Parlange, J.-Y., “Radial movement of saturated zone under constant flux: Theory and application to the determination of soil-water diffusivity”, Soil Sci. Soc. Am. J. 40 (1976), 635639.CrossRefGoogle Scholar
[12]Smith, R. E. and Parlange, J.-Y., “Optimal prediction of ponding”, Trans. ASAE 20 (1977), 493496.CrossRefGoogle Scholar
[13]Turner, N. C. and Parlange, J.-Y., “Two-dimensional similarity solution: Theory and application to the determination of soil-water diffusivity”, Soil Sci. Soc. Am. Proc. 39 (1975), 387390CrossRefGoogle Scholar