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The inertial migration of non-neutrally buoyant spherical particles in two-dimensional shear flows

Published online by Cambridge University Press:  26 April 2006

Andrew J. Hogg*
Affiliation:
Institute of Theoretical Geophysics, Department of Applied Mathematics & Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW, UK

Abstract

The inertial migration of a small rigid spherical particle, suspended in a fluid flowing between two plane boundaries, is investigated theoretically to find the effect on the lateral motion. The channel Reynolds number is of order unity and thus both boundary-induced and Oseen-like inertial migration effects are important. The particle Reynolds number is small but non-zero, and singular perturbation techniques are used to calculate the component of the migration velocity which is directed perpendicular to the boundaries of the channel. The particle is non-neutrally buoyant and thus its buoyancy-induced motion may be either parallel or perpendicular to the channel boundaries, depending on the channel alignment. When the buoyancy results in motion perpendicular to the channel boundaries, the inertial migration is a first-order correction to the magnitude of this lateral motion, which significantly increases near to the boundaries. When the buoyancy produces motion parallel with the channel boundaries, the inertial migration gives the zeroth-order lateral motion either towards or away from the boundaries. It is found that those particles which have a velocity exceeding the undisturbed shear flow will migrate towards the boundaries, whereas those with velocities less than the undisturbed flow migrate towards the channel centreline. This calculation is of practical importance for various chemical engineering devices in which particles must be filtered or separated. It is useful to calculate the forces on a particle moving near to a boundary, through a shear flow. This study may also explain certain migration effects of bubbles and crystals suspended in molten rock flow flowing through volcanic conduits.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1994

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References

Abbott, J. E. & Francis, J. R. D. 1977 Saltation and suspension trajectories of solid grains in a water stream. Phil. Trans. R. Soc. Lond. A 284, 225254.Google Scholar
Batchelor, G. K. 1965 An Introduction to Fluid Dynamics. Cambridge University Press.Google Scholar
Brenner, H. 1961 The slow motion of a sphere through a viscous fluid towards a plane surface. Chem. Engng Sci. 16, 242251.Google Scholar
Bretherton, F. P. 1962 The motion of rigid particles in a shear flow at low Reynolds number. J. Fluid Mech. 14, 284304.Google Scholar
Brousse, R. 1965 Observations sur les dykes et leur prismation. Congrès des Sociétés Sauvant, Nice.Google Scholar
Cox, R. G. & Hsu, S. K. 1977 The lateral migration of solid particles in a laminar flow near a plane. Intl. J. Multiphase Flow 3, 201222.Google Scholar
Drew, D. A. 1978 The force on a small sphere in slow viscous flow. J. Fluid Mech. 88, 393400.Google Scholar
Drew, D. A. 1988 The lift force on a small sphere in the presence of a wall. Chem. Engng Sci. 43, 769773.Google Scholar
Eichhorn, R. & Small, S. 1964 Experiments on the lift and drag of spheres suspended in a Poiseuille flow. J. Fluid Mech. 20, 513527.Google Scholar
Ganatos, P., Weinbaum, S. & Pfeffer, R. 1980 A strong interaction theory for the creeping motion of a sphere between parallel boundaries. Part 1: Perpendicular motion. J. Fluid Mech. 99, 739753.Google Scholar
Giddings, J. C., Myers, M. N., Moon, M. H. & Barman, B. N. 1991 Particle separation and size characterisation by sedimentation field-flow fractionation. Particle-Size Distribution II. ACS Symposium Series 472, Provder.CrossRefGoogle Scholar
Happel, J. & Brenner, H. 1965 Low Reynolds Number Hydrodynamics. Prentice-Hall.Google Scholar
Harper, E. Y. & Chang, I.-D. 1968 Maximum dissipation resulting from lift in slow viscous flow. J. Fluid Mech. 33, 209225.Google Scholar
Hinch, E. J. 1992 Perturbation Methods. Cambridge University Press.CrossRefGoogle Scholar
Ho, B. P. & Leal, L. G. 1974 Inertial migration of rigid spheres in two dimensional unidirectional flows. J. Fluid Mech. 65, 365400.Google Scholar
Jeffrey, R. C. & Pearson, J. R. A. 1965 Particle motion in laminar vertical tube flow. J. Fluid Mech. 22, 721735.Google Scholar
Lamb, H. 1932 Hydrodynamics. Cambridge University Press.Google Scholar
Lin, C.-J., Perry, J. H. & Schowalter, W. R. 1970 Simple shear flow round a rigid sphere: inertial effects and suspension rheology. J. Fluid Mech. 44, 117.Google Scholar
Lister, J. R. & Kerr, R. C. 1991 Fluid-mechanical models of crack propagation and their application to magma transport in dykes. J. Geophys. Res. 96B, 1004910077.Google Scholar
McLaughlin, J. B. 1991 Inertial migration of a small sphere in linear shear flows. J. Fluid Mech. 224, 261274.Google Scholar
McLaughlin, J. B. 1993 The lift on a small sphere in wall-bounded linear shear flows. J. Fluid Mech. 246, 249265.Google Scholar
Saffman, P. G. 1965 The lift on a small sphere in slow shear flow. J. Fluid Mech. 22, 385400, and Corrigendum J. Fluid Mech. 31, 1968, 624.Google Scholar
Schonberg, J. A. & Hinch, E. J. 1989 Inertial migration of a sphere in Poiseuille flow. J. Fluid Mech. 203, 517524.Google Scholar
Segré, G. & Silberberg, A. 1962a Behaviour of macroscopic rigid spheres in Poiseuille flow. Part 1. Determination of local concentration by statistical analysis of particle passages through crossed light beams. J. Fluid Mech. 14, 115135.CrossRefGoogle Scholar
Segré, G. & Silberberg, A. 1962b Behaviour of macroscopic rigid spheres in Poiseuille flow. Part 2. Experimental results and interpretation. J. Fluid Mech. 14, 136157.Google Scholar
Shibata, M. & Mei, C. C. 1990 Inertia effects of a localised force distribution near a wall in a slow shear flow. Phys. Fluids A 2, 10941104.Google Scholar
Vasseur, P. & Cox, R. G. 1976 The lateral migration of a spherical particle in two dimensional shear flows. J. Fluid Mech. 78, 385413.Google Scholar
Vasseur, P. & Cox, R. G. 1977 The lateral motion of spherical particles sedimenting in a stagnant bounded fluid. J. Fluid Mech. 80, 561591.Google Scholar