Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-28T02:18:32.240Z Has data issue: false hasContentIssue false

Groups defined on images in fluid diffusion

Published online by Cambridge University Press:  17 February 2009

A. J. Bracken
Affiliation:
Department of Mathematics, University of Queensland, St Lucia, Queensland, 4067.
H. S. Green
Affiliation:
Department of Mathematics, University of Queensland, St Lucia, Queensland, 4067. Department of Mathematical Physics, University of Adelaide, South Australia, 5001.
L. Bass
Affiliation:
Department of Mathematics, University of Queensland, St Lucia, Queensland, 4067.
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.

A method based on the method of images is described for the solution of the linear equation modelling diffusion and elimination of substrate in a fluid flowing through a chemical reactor of finite length, when the influx of substrate is prescribed at the point of entry and Danckwerts' zero-gradient condition is imposed at the point of exit. The problem is shown to be transformable to an equivalent problem in heat conduction. Associated with the images appearing in the method of solution is a sequence of functions which form a vector space carrying a representation of the Lie group SO(2, 1) generated by three third-order differential operators. The functions are eigenfunctions of one of these operators, with integer-spaced eigenvalues, and they satisfy a third-order recurrence relation which simplifies their successive determination, and hence the determination of the Green's function for the problem, to any desired degree of approximation. Consequently, the method has considerable computational advantages over commonly used methods based on the use of Laplace and related transforms. Associated with these functions is a sequence of polynomials satisfying the same third-order differential equation and recurrence relation. The polynomials are shown to bear a simple relationship to Laguerre polynomials and to satisfy the ordinary diffusion equation, for which SO(2, 1) is therefore revealed as an invariance group. These diffusion polynomials are distinct from the well-known heat polynomials, but a relationship between them is derived. A generalised set of diffusion polynomials, based on the associated Laguerre polynomials, is also described, having similar properties.

Type
Research Article
Copyright
Copyright © Australian Mathematical Society 1988

References

[1]Abramowitz, M. and Stegun, I. A., Handbook of Mathematical Functions (U.S. Nat. Bur. of Standards, Washington, 1964).Google Scholar
[2]Askey, R. A., Koornwinder, T. H. and Schemp, W. (eds.), Special Functions: Group Theoretical Aspects (D. Reidel, Dordrecht, 1984).Google Scholar
[3]Barut, A. O. and Fronsdal, C., Proc. Roy. Soc. London Ser. A 287 (1965) 532548.Google Scholar
[4]Bass, L., Bracken, A. J. and Green, H. S., sub. Chem. Engng. Sci. (1987).Google Scholar
[5]Bluman, G. W. and Cole, J. D., J. of Math. and Mech., 18 (1969) 10251042;Google Scholar
see also Bluman, G. W. and Cole, J. D., Similarity Methods for Differential Equations (Springer, Berlin: Applied Mathematical Sciences Series 13, 1974).Google Scholar
[6]van Cauwenberghe, A. R., Chem. Engng. Sci., 21 (1966) 203205.Google Scholar
[7]Danckwerts, P. V., Chem. Engng. Sci., 2 (1953) 113.Google Scholar
[8]Deckwer, W. and Mählmann, E. A., Adv. Chem., 133 (1974) 334347.Google Scholar
[9]Deckwer, W. and Mählmann, E. A., Chem. Engng. J., 11 (1976) 1925.CrossRefGoogle Scholar
[10]Dennemeyer, R., Introduction to Partial Differential Equations and Boundary Value Problems (McGraw-Hill, New York, 1968).Google Scholar
[11]Dieudonné, J. A., Special Functions and Linear Representations of Lie Groups (Amer. Math. Soc., Providence, R.I., 1980).Google Scholar
[12]Erdelyi, A. (ed.), Bateman Manuscript Project Vol. 1 (1953) (McGraw-Hill, New York, 1953).Google Scholar
[13]Green, H. S., “Pollution by Diffusive Processes”. Pollution: Engineering and Scientific Solutions (ed. Barrekette, E. S.) (Plenum, New York, 1973).Google Scholar
[14]Green, H. S. and Triffet, T., J. Math. Phys. 10 (1969) 10691089.Google Scholar
[15]Miller, W., Lie Theory and Special Functions (Academic Press, New York, 1968).Google Scholar
[16]Parulekar, S. J. and Ramakrishna, D., Chem. Engng. Sci., 39 (1980) 15711579, 1581–1597, 1599–1611.Google Scholar
[17]Perl, W. and Chinard, F. P., Circulation Research 22 (1968) 273298.CrossRefGoogle Scholar
[18]Roberts, M. S. and Rowland, M., J. Pharmacokinet. Biopharm. 14 (1986) 227308.CrossRefGoogle Scholar
[19]Sommerfeld, A., Partial Differential Equations in Physics (Academic Press, New York, 1949).Google Scholar
[20]Sundaresan, S., Amundson, N. R. and Aris, R., AIChE J., 26 (1980) 529536.CrossRefGoogle Scholar
[21]Vandenberg, A. M. and Deakin, M. A. B., History of Mathematics Papers 36 (Maths. Dept., Monash Univ., 1986) 196.Google Scholar
[22]Wehner, J. F. and Wilhelm, R. H., Chem. Engng. Sci., 6 (1956) 8993.CrossRefGoogle Scholar
[23]Wen, C. Y. and Fan, L. T., Models for Flow Systems in Chemical Reactors (M. Dekker, New York, 1975).Google Scholar
[24]Wicke, E., Chemie-ing.-Techn. 47 (1975) 547551.CrossRefGoogle Scholar
[25]Widder, D. V., The Heat Equation (Academic Press, New York, 1975).Google Scholar