Numerical Modeling of Self-Aeration in High-Speed Flows over Smooth Chute Spillways
Publication: Journal of Hydraulic Engineering
Volume 149, Issue 3
Abstract
In chute spillways, self-aeration occurs downstream of the inception point, where the turbulent boundary layer edge approaches the free surface, if they are long enough. Downstream of the inception point, a layer containing an air–water mixture extends gradually through the flow with the bulking effect. Flow bulking is essential in terms of sidewall freeboard design. In addition, the introduction of enough air quantity near the solid boundaries prevents cavitation damage. In the present work, a 2D numerical model was developed for the prediction of self-aeration and air concentration profiles across the depth and the free-surface location, together with flow bulking along the smooth chutes. The developed model deals with the solution of the one-way direction parabolic equations of mixture continuity, air mass, and air–water mixture momentum conservation. These equations are solved accompanied by the dynamic equation for the free surface, utilizing the marching technique and Prandtl’s mixing length turbulent model. The experimental data obtained by prototype measurements and laboratory tests were used to assess the accuracy of the numerical model. The relevant results were compared in terms of the induced inception point of the boundary layer development, air concentration profiles within self-entrained flows, and the consequent bulking of the flow. The capability of the numerical model for practical purposes is signified in accordance with the fairly accurate obtained results, shedding light on new horizons for further research.
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Data Availability Statement
The code generated and used during the present study is available in a repository online (https://github.com/Jalili47/ChuteAer) in accordance with funder data retention policies.
Acknowledgments
The third author would like to acknowledge the Iranian National Elites Foundation for financial support (Grant INEF-AUT 20/142/2017).
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Journal of Hydraulic Engineering
Volume 149 • Issue 3 • March 2023
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© 2022 American Society of Civil Engineers.
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Received: May 15, 2021
Accepted: Sep 30, 2022
Published online: Dec 21, 2022
Published in print: Mar 1, 2023
Discussion open until: May 21, 2023
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