The Effect of Bubble Size on Lock-Exchange Density Currents through Bubble Screens
Publication: Journal of Hydraulic Engineering
Volume 150, Issue 3
Abstract
Bubble screens are used at sea locks to mitigate salt intrusion into inland water systems. In this paper the effectiveness of a bubble screen in delaying the mixing of salt and freshwater via lock exchange was studied. Laboratory-scale experiments investigating the flow field and mixing caused by a bubble screen are presented. The tests include both the homogeneous situation of freshwater on both sides of the screen and the inhomogeneous situation where there is an initial density difference across the screen, which leads to a density current after the lock gate is removed or opened. Optical measurement techniques were applied, giving spatially detailed flow velocities and densities. The parameters varied between tests are the airflow discharge and the bubble size. The results show that the bubble size in the screen had a significant effect with a screen with bubbles of 1–2 mm being more effective at generating a surface flow in the homogeneous case but less effective at keeping the fresh and salt sides separated in the inhomogeneous case, when compared with a screen of 4–6 mm bubbles. The point of maximum effectiveness for separating salt and fresh sides was also shown to be dependent on bubble size.
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Data Availability Statement
All data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
The authors wish to acknowledge the help of several students and colleagues in the preparation, execution, and analysis of this experiments: Babette Haitsma Mulier, Bart Veenings, Gijs Verbeeten, Gijs Wolbert, Pam van Zaanen, Lina Nikolaidou, and Jesil Kurian. We thank Helena Nogueira for careful reading and helpful comments on the drafts of the paper. In particular, the authors would like to thank Arthur Oldeman and colleagues from the Technical University of Eindhoven for their assistance in processing the data and discussions. This work was conducted with Topconsortium voor Kennis en Innovatie (TKI) funding from the Dutch Ministry of Economic Affairs (Grant #2017DEL002).
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Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 150 • Issue 3 • May 2024
Copyright
© 2024 American Society of Civil Engineers.
History
Received: Oct 7, 2022
Accepted: Aug 25, 2023
Published online: Feb 15, 2024
Published in print: May 1, 2024
Discussion open until: Jul 15, 2024
ASCE Technical Topics:
- Chemical compounds
- Chemicals
- Chemistry
- Coastal engineering
- Coastal processes
- Coasts, oceans, ports, and waterways engineering
- Density currents
- Engineering fundamentals
- Environmental engineering
- Field tests
- Flow measurement
- Fluid dynamics
- Fluid mechanics
- Fresh water
- Homogeneity
- Hydrologic engineering
- Material mechanics
- Material properties
- Materials engineering
- Measurement (by type)
- Ocean currents
- Salt water
- Salt water intrusion
- Salts
- Tests (by type)
- Water (by type)
- Water and water resources
- Water management
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