Velocity of Particles Falling in Vertically Oscillating Flow
Publication: Journal of Hydraulic Engineering
Volume 116, Issue 1
Abstract
The instantaneous velocity of particles driven by an oscillating flow can be determined by means of Fourier analysis. A simple numerical method based on the principle of least square error is presented to obtain the solutions of the Fourier coefficients. The computed zeroth harmonic term, which is the effective fall velocity and is less than the terminal velocity in still fluid, is in good agreement with experimental observations. The reduced velocity is caused by the nonlinear modification of the drag force exerted on the particle by the fluid because the relative velocity between the particle and the fluid is no longer the constant terminal velocity. There are three parameters that determine the effectiveness of fall velocity reduction: The terminal velocity Reynolds number, the ratio of the flow velocity amplitude to the terminal velocity, and a quantity characterizing the frequency response of the particle to the unsteadiness of the flow motion.
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References
1.
Brash, L. M., Ho, H.‐W., and Yen, B.‐C. (1964). “Accelerated motion of a sphere in a viscous fluid.” J. Hydr. Engrg., ASCE, 90(1), 149–160.
2.
Davis, H. T. (1962). Introduction to nonlinear differential and integral equations. Dover Publications, Inc., New York, N.Y.
3.
Farber, K. (1987). Discussion of “Fall velocity of particles in oscillating flow,” by P. A. Hwang, J. Hydr. Engrg., ASCE, 113(7), 935.
4.
Ho, H. W. (1964). “Fall velocity of a sphere in a field of oscillating fluid,” thesis presented to the State Unversity of Iowa, at Iowa City, Iowa, in partial fulfillmentof the requirements for the degree of Doctor of Philosophy.
5.
Hwang, P. A. (1985). “Fall velocity of particles in oscillating flow.” J. Hydr. Engrg., ASCE, 111(3), 485–502
6.
Marion, J. B. (1970). Classical dynamics of particles and systems. Academic Press, New York, N.Y.
7.
Nielson, P. (1987). Discussion of “Fall velocity of particles in oscillating flow,” by P. A. Hwang, J. Hydr. Engrg., ASCE, 113(7), 935–938.
8.
Torobin, L. B., and Gauvin, W. H. (1960). “Fundamental aspects of solids‐gas flow. part V. The effects of fluid turbulence on the particle drag coefficient.” Can. J. Chem. Engrg., 38(12), 189–200.
9.
Wells, M. R., and Stock, D. E. (1983). “The effects of crossing trajectories on the dispersion of particles in a turbulent flow.” J. Fluid Mech., 136, 31–62.
Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 116 • Issue 1 • January 1990
Pages: 23 - 35
Copyright
Copyright © 1990 ASCE.
History
Published online: Jan 1, 1990
Published in print: Jan 1990
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