Hostname: page-component-cd9895bd7-dk4vv Total loading time: 0 Render date: 2024-12-19T05:49:10.340Z Has data issue: false hasContentIssue false

Diffusion of Brownian particles in shear flows

Published online by Cambridge University Press:  19 April 2006

R. T. Foister
Affiliation:
Department of Chemistry, McGill University, Montreal, Canada and Pulp and Paper Research Institute of Canada, Montreal, Canada
T. G. M. Van De Ven
Affiliation:
Department of Chemistry, McGill University, Montreal, Canada and Pulp and Paper Research Institute of Canada, Montreal, Canada

Abstract

The coupling of Brownian displacements and shear-induced convection of spherical colloidal particles in dilute suspensions is examined using solutions of appropriate convective diffusion equations for the time-dependent probability density and also by calculation of relevant statistical quantities for an ensemble of diffusing particles from Langevin equations. Based on a fundamental solution for convective diffusion from a point in a general linear field, analytical expressions for the probability density fα(r; t) are given for the case of an arbitrary, two-dimensional linear flow field. The parameter α, which characterizes the flow, may range from − 1 (pure rotation), through zero (simple shear), to + 1 (pure elongation). The Langevin approach offers interesting insights into the physical mechanism of diffusive–convective coupling, and may also be used to obtain rigorous expressions for moments of the probability density appropriate to a particle diffusing in an unbounded quadratic (Poiseuille) flow. Preliminary experiments are described which qualitatively verify the theoretical predictions for Poiseuille flow, and which suggest a simple, direct method for measuring particle diffusivities. Finally the effect of bounding walls on convective diffusion is considered by means of Monte Carlo calculations. Results show that particle-wall interactions significantly affect the average behaviour of particles located initially within distances of a few particle radii of the wall, since the frictional force is no longer isotropic.

Type
Research Article
Copyright
© 1980 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Adelman, S. A. 1976 J. Chem. Phys. 64, 124.
Bedeaux, D. & Mazur, P. 1974 Physica (Utrecht) A 76, 247.
Booth, F. 1950 Proc. Roy. Soc. A 203, 514.
Brenner, H. & Gaydos, L. J. 1977 J. Colloid Interface Sci. 58, 312.
Brinkman, H. 1956 Physica (Utrecht) 22, 29.
Chandrasekhar, S. 1943 Rev. Mod. Phys. 15, 1.
Chatwin, P. C. 1976 J. Fluid Mech. 77, 593.
Chatwin, P. C. 1977 J. Fluid Mech. 80, 33.
Chow, T. S. & Hermans, J. J. 1972 J. Chem. Phys. 56, 3150.
Elrick, D. E. 1962 Aust. J. Phys. 15, 283.
Ermak, D. L. & McCammon, J. A. 1978 J. Chem. Phys. 69, 1352.
Foister, R. T. & Hermans, J. J. 1977 Macromolecules 10, 1043.
Giddings, J. C. 1966 Sep. Sci. 1, 123.
Gill, W. N. & Sankarasubramanian, R. 1970 Proc. Roy. Soc. A 316, 341.
Gill, W. N. & Sankarasubramanian, R. 1971 Proc. Roy. Soc. A 322, 101.
Goldman, A. J., Cox, R. G. & Brenner, H. 1967a Chem. Engng Sci. 22, 637.
Goldman, A. J., Cox, R. G. & Brenner, H. 1967b Chem. Engng Sci. 22, 653.
Happel, J. & Brenner, H. 1973 Low Reynolds Number Hydrodynamics, p. 67. Leiden: Nordhoff.
Hinch, E. J. 1975 J. Fluid Mech. 72, 499.
Kao, S. V., Cox, R. G. & Mason, S. G. 1977 Chem. Engng Sci. 32, 1505.
Kao, S. V., Powell, R. L. & Mason, S. G. 1979 (to appear).
Kramers, H. A. 1940 Physica (Utrecht) 7, 284.
Krishnamurthy, S. & Subramanian, R. S. 1977 Sep. Sci. 12, 347.
Leal, L. G. & Hinch, E. J. 1971 J. Fluid Mech. 46, 685.
Lighthill, M. J. 1966 J. Inst. Math. Appl. 2, 97.
Lorentz, H. A. 1921 Lessen over Theoretische Natuurkunde. V. Kinetische Problemen. Leiden.
Mason, S. G. 1976 J. Colloid Interface Sci. 58, 275.
Morse, P. M. & Feshbach, H. 1953 Methods of Theoretical Physics, p. 857. McGraw-Hill.
Saffman, P. G. 1960 J. Fluid Mech. 8, 273.
Saffman, P. G. 1976 J. Fluid Mech. 73, 593.
Taylor, G. I. 1953 Proc. Roy. Soc. A 219, 186.
Vadas, E., Cox, R. G., Goldsmith, H. L. & Mason, S. G. 1976 J. Colloid Interface Sci. 57, 308.
Vadas, E., Goldsmith, H. L. & Mason, S. G. 1973 J. Colloid Interface Sci. 43, 630.
Ven, T. G. M. van de 1977 J. Colloid Interface Sci. 62, 352.
Ven, T. G. M. van de & Mason, S. G. 1976 J. Colloid Interface Sci. 57, 517.
Ven, T. G. M. van de & Mason, S. G. 1977 Colloid & Polymer Sci. 255, 794.
Ven, T. G. M. van de, Takamura, K. & Mason, S. G. 1979 (to appear).
Wang, M. C. & Uhlenbeck, G. E. 1945 Rev. Mod. Phys. 17, 323.
Zuzovsky, M., Priel, Z. & Mason, S. G. 1979 (to appear).