Hostname: page-component-cd9895bd7-lnqnp Total loading time: 0 Render date: 2024-12-29T13:29:36.175Z Has data issue: false hasContentIssue false

The contraction of contaminant distributions in reversing flows

Published online by Cambridge University Press:  20 April 2006

Ronald Smith
Affiliation:
Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CBS 9EW

Abstract

Exact expressions are derived for the centroid and variance as functions across the flow when there has been an initially uniform contaminant release in an oscillatory flow. Two examples are given to demonstrate that there can be a substantial region of the flow (where the velocity shear is relatively large) in which the contaminant distribution exhibits contraction after flow reversal. This effect, and the sensitivity of the variance to the precise time of discharge, is most marked when the flow oscillations are rapid relative to the timescale for cross-sectional mixing.

Type
Research Article
Copyright
© 1983 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

Abramowitz, M. & Stegun, I. A. 1965 Handbook of Mathematical Functions. Dover.
Allen, C. M. 1982 Numerical simulation of contaminant dispersion in estuary flows Proc. R. Soc. Lond. A381, 179184.Google Scholar
Aris, R. 1956 On the dispersion of a solute in a fluid flowing through a tube Proc. R. Soc. Lond. A235, 6777.Google Scholar
Bowden, K. F. 1965 Horizontal mixing in the sea due to a shearing current J. Fluid Mech. 21, 8395.Google Scholar
Bowden, K. F. & Fairbairn, L. A. 1952 A determination of the frictional forces in a tidal current Proc. R. Soc. Lond. A214, 371392.Google Scholar
Chatwin, P. C. 1970 The proach to normality of the concentration distribution of a solute in a solvent flowing along a straight pipe. J. Fluid Mech. 43, 321352.Google Scholar
Chatwin, P. C. 1975 On the longitudinal dispersion of passive contaminant in oscillatory flows in tubes J. Fluid Mech. 71, 513527.Google Scholar
Csanady, G. T. 1973 Turbulent Diffusion in the Environment. Reidel.
Fischer, H. B. 1972 Mass transport mechanisms in partially stratified estuaries J. Fluid Mech. 53, 671687.Google Scholar
Holley, E. R., Harleman, D. R. F. & Fischer, H. B. 1970 Dispersion in homogeneous estuary flow J. Hydraul. Div. A.S.C.E. 96, 703724.Google Scholar
Smith, R. 1982a Contaminant dispersion in oscillatory flows J. Fluid Mech. 114, 379398.Google Scholar
Smith, R. 1982b Dispersion of tracers in the deep ocean J. Fluid Mech. 123, 131142.Google Scholar
Smith, R. 1982c Gaussian approximation for contaminant dispersion Q. J. Mech. Appl. Math. 35, 345366.Google Scholar
Sullivan, P. J. 1974 Instantaneous velocity and length scales in a turbulent shear flow Adv. Geophys. 18A, 213223.Google Scholar