Reduction of the Flow Separation Zone at Combining Open-Channel Junction by Applying Alternate Suction and Blowing
Publication: Journal of Irrigation and Drainage Engineering
Volume 147, Issue 10
Abstract
The flow separation zone (FSZ) is one of the main flow characteristics of the combining open channel junction and is associated with energy dissipation. Bed shear stress in the contracted flow region increases as the channel’s effective width is reduced. Reduction of the FSZ at the junction to improve efficiency is desirable. The present numerical study focuses on the effect of continuous suction and blowing perturbations in reducing the FSZ at a right-angled open channel junction. The flow field is simulated using computational fluid dynamics (CFD) software. The numerical model is validated by comparing the simulated velocity field, water surface elevation, and energy loss for the unperturbed junction flow with corresponding experimental results available in the literature. The continuous suction and blowing perturbation is generated by a sinusoidal function with zero net discharge and is applied through a rectangular slit. Three different slit locations are considered downstream of the junction. The simulated results (time-averaged) show that the sinusoidal perturbation is effective in reducing the dimensions of the FSZ and, consequently, the energy loss and bed shear stress. The results demonstrate the enhanced effectiveness in reducing the energy loss when the slit is more proximate to the junction for the chosen flow configuration and the sinusoidal perturbation characteristics. The results of the time-averaged depth ratios show only a marginal reduction due to the flow perturbation.
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Data Availability Statement
Some or all of the data, models, or code that support the findings of this study (Ansys Fluent file, post-processing code) are available from the corresponding author upon reasonable request.
Acknowledgments
The anonymous reviewers are gratefully acknowledged for their valuable suggestions. The authors also acknowledge the financial help provided by Prime Minister Research Fellowship and IIT Gandhinagar to conduct this study.
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Journal of Irrigation and Drainage Engineering
Volume 147 • Issue 10 • October 2021
Copyright
© 2021 American Society of Civil Engineers.
History
Received: Nov 30, 2020
Accepted: Jun 7, 2021
Published online: Aug 13, 2021
Published in print: Oct 1, 2021
Discussion open until: Jan 13, 2022
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