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Optimal discharge profiles for sudden contaminant releases in steady, uniform open-channel flow

Published online by Cambridge University Press:  20 April 2006

N. C. Daish
N. C. Daish
Affiliation:
Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW
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Abstract

The effect of varying the initial concentration distribution is investigated for a sudden contaminant release in a uniform straight channel. Taking the optimal choice to be that which maximizes the variance of the contaminant cloud far downstream, it is found that, unless the topography is very unusual, the largest variance can be generated by splitting the contaminant into two parts, placing the larger part at the bank where the channel bed slopes most gently, and the remainder near to where the channel is deepest. This procedure significantly reduces peak concentrations far downstream when compared with making the entire release at any single point across the flow. Even at distances as large as six times the e-folding distance for cross-sectional mixing, the splitting of the discharge is shown to reduce the peak concentrations by a third.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 159 , October 1985 , pp. 303 - 321
Copyright
© 1985 Cambridge University Press

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