Effect of Weir Face Angles on Circular-Crested Weir Flow
Publication: Journal of Hydraulic Engineering
Volume 137, Issue 6
Abstract
The standard circular-crested weir is often found in engineering applications and is used as a discharge measurement device or as an overflow structure. This research determines the discharge coefficients for ten circular-crested weir configurations with various combinations of up- and downstream angles. Two different weir heights and four different overflow depths are considered for each weir shape. For free overflow, the discharge coefficient is determined experimentally by using the total head of the approach flow. The results indicate that the upstream weir face angle has only a small effect on the discharge coefficient. In contrast, increasing the downstream weir face angle increases the discharge coefficient notably. A new formula for the discharge coefficient is presented, including both the up- and downstream weir face angles. Further, the hydraulic performance of the circular-crested weir, the resulting discharge reduction from tailwater submergence, and transition flow are discussed.
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Acknowledgments
The first author was supported by the Swiss National Science Foundation, Grant No. NSF-CH200020-116680.
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Published In
Journal of Hydraulic Engineering
Volume 137 • Issue 6 • June 2011
Pages: 637 - 643
Copyright
© 2011 American Society of Civil Engineers.
History
Received: Mar 24, 2010
Accepted: Oct 10, 2010
Published online: May 16, 2011
Published in print: Jun 1, 2011
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