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The measurement of velocity gradients in laminar flow by homodyne light-scattering spectroscopy

Published online by Cambridge University Press:  19 April 2006

G. G. Fuller
Affiliation:
Department of Chemical Engineering, California Institute of Technology, Pasadena, California 91125
J. M. Rallison
Affiliation:
Department of Chemical Engineering, California Institute of Technology, Pasadena, California 91125
R. L. Schmidt
Affiliation:
Department of Chemical Engineering, California Institute of Technology, Pasadena, California 91125
L. G. Leal
Affiliation:
Department of Chemical Engineering, California Institute of Technology, Pasadena, California 91125

Abstract

A technique for measuring velocity gradients in laminar flows by homodyne light scattering is presented. A theory which describes the light-scattering spectrum is derived that includes the effects of different types of linear flow fields, particle diffusion and the intensity profile in the scattering volume. The conditions which must be satisfied in order that the theory describe the experimental situation are outlined and complementary experiments are performed which both verify the theory and apply the technique. Verification is provided using the flow in a Couette device, and the flow due to single rotating cylinder in a large bath of fluid. The technique is then applied to measure the spatial variation of the shear rate in a four-roll mill.

Type
Research Article
Copyright
© 1980 Cambridge University Press

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