Effect of Shallowness on Dilution of Unidirectional Diffusers
Publication: Journal of Hydraulic Engineering
Volume 145, Issue 12
Abstract
The effect of receiving water depth on the dilution of a unidirectional diffuser discharging dense effluent in quiescent conditions is analyzed. Dilution measurements from previous studies are reviewed to determine the effect of shallowness on the mixing of submerged single port outfalls. For a unidirectional multiport diffuser, the width of the effluent plume is observed to contract in shallow water. A model is proposed relating the dilution of a unidirectional diffuser to the dilution of a single jet using the contracted width. Measurements of the contracted width in shallow water are made to support the proposed model, which is verified by additional measurements of dilution. Three flow regimes, namely, deep, shallow, and vertically mixed, are identified based on the value of . Here, is the diameter of the jet, is the densimetric Froude number of the jet, and is the depth of receiving water. It is shown that shallow water depth affects the dilution in two ways—the dilution of individual jets is reduced, and the contraction in plume width leads to further reduction in dilution.
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Data Availability Statement
All data, models, and code generated or used during the study appear in the submitted article.
Acknowledgments
This work was supported by Kuwait-MIT Center for Natural Resources and the Environment (CNRE), which was funded by Kuwait Foundation for the Advancement of Sciences (KFAS).
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Published In
Journal of Hydraulic Engineering
Volume 145 • Issue 12 • December 2019
Copyright
©2019 American Society of Civil Engineers.
History
Received: Feb 26, 2018
Accepted: Mar 28, 2019
Published online: Sep 24, 2019
Published in print: Dec 1, 2019
Discussion open until: Feb 24, 2020
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