Critical Submergence for Single Lateral Rectangular Hydraulic Intakes under Uniform Approach Flow
Publication: Journal of Hydraulic Engineering
Volume 150, Issue 6
Abstract
An air-entraining vortex begins to form when the submergence of an intake is not adequate and less than the critical value known as critical submergence. In the present study, critical submergence for a laterally placed single rectangular intake under a uniform approach flow in an open channel was investigated experimentally. Analysis of the data collected in the present study reveals that critical submergence is significantly influenced by intake size, intake aspect ratios, approach Froude number, intake Froude number, intake Reynolds number, and Weber number. However, intake Froude number and intake aspect ratio were found to be the most sensitive parameters that affect critical submergence. An empirical relationship for critical submergence has been developed using collected data used to compute the critical submergence within an error of . The findings of this investigation is advantageous for hydraulic engineers when designing lateral rectangular intakes to prevent the formation of an air-entraining vortex.
Practical Applications
Insufficient water cover over the hydraulic intakes causes an air-entraining vortex formation in the vicinity of the intake. The formation of such an air-entraining vortex results in significant hydraulic issues, structural damages, etc. Ensuring enough submergence for the intake during its operational period is necessary to evade such problems. The submergence at which the air-core tail of the surface vortex reaches the intake initiating air-entrainment is called critical submergence. Critical submergence is an important parameter for the design of intakes and is widely used as a parameter to determine an incipient state for which no air is entrained by intake vortices. This paper discusses the experimental investigation of critical submergence for single lateral rectangular intakes concerning significant geometrical parameters, such as intake aspect ratio, approach Froude number, intake Froude number, etc. The proposed empirical equations in this study are helpful to hydraulic engineers when computing critical submergence to fix the invert level of a lateral rectangular intake.
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Data Availability Statement
All data, models, and code generated or used during the study appear in the published article.
Acknowledgments
The first author is very appreciative of the scholarship received from the Ministry of Education, Government of India.
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© 2024 American Society of Civil Engineers.
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Received: Aug 6, 2023
Accepted: Jul 16, 2024
Published online: Sep 4, 2024
Published in print: Nov 1, 2024
Discussion open until: Feb 4, 2025
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