Hydrodynamic Structure and Turbulent Characteristics of Low-Slope Bedrock Bend Reach with Constant Curvature
Publication: Journal of Hydraulic Engineering
Volume 148, Issue 9
Abstract
Recent studies have indicated that low-slope bedrock reaches are more common in nature (the bedrock surface slope is slightly lower than 0.005). This paper focuses on the hydrodynamic structure and turbulent characteristics of low-slope and critically sharp bedrock bends under flood conditions. Three experiments under different flood frequencies were conducted to investigate the influence of the ratio of centerline curvature radius to depth () on the distribution and characteristics of the secondary flow, turbulence, and momentum transport measured by acoustic Doppler velocimeter (ADV). The results were then compared with the flow structure of a sharp bend. Our results indicated that the distribution area and the intensity of the secondary flow decreased with , especially in the outer-bank cell and the center-region cell. The lower was, the more obvious the flow separation at the inner bank was. The core area of the turbulent kinetic energy moved upstream gradually, and its intensity increased with . The friction factor increased in the upstream bend and did not move further upstream when was below 13.6. The intensity of the transverse bed shear stress decreased with in a critically sharp bend, and the maximum value near the upstream centerline implied the potential erosion in the bedrock bend. These experimental results are conducive to understanding the flow process of erosion and deposition in the bedrock bend reach.
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Data Availability Statement
All data that support the findings of this study are available from Bin Li at [email protected] upon request.
Acknowledgments
This study was funded by the National Natural Science Foundation of China (Grant Nos. 51979185 and 51879182). Yiyao Zhou is acknowledged for assisting in this research.
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Published In
Journal of Hydraulic Engineering
Volume 148 • Issue 9 • September 2022
Copyright
© 2022 American Society of Civil Engineers.
History
Received: Aug 19, 2021
Accepted: Apr 1, 2022
Published online: Jun 24, 2022
Published in print: Sep 1, 2022
Discussion open until: Nov 24, 2022
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