Overflow characteristics of circular-crested weirs

Abstract

Circular-crested weirs are one of simplest types of hydraulic structures used for discharge measurement and regulation of open channel flow. In the present study, the flow over a circular-crested weir was simulated with an irrotational vortex to determine the weir discharge coefficient and velocity values over the crest. Two dimensionless parameters including circulation and curvature coefficient were defined and determined experimentally. The results show that these parameters could be presented by power equations. To develop and evaluate the proposed method, physical models of circular-crested weirs, containing various radii, heights and slopes, were investigated. It was found that this method produces the main features of weir flow reasonably well.

Keywords:

• Circular-crested weir
• circulation
• discharge coefficient
• irrotational vortex
• velocity distribution

Acknowledgements

The writers would like to thank Mr Eghbal Khorami for preparing the experimental set-up and collecting the data.