Calibration of unsteady flow in Crump Weir

Document Type : Research Article


1 Department of Civil Engineering, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran

2 Department of Civil Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran


Crump weir is widely used to measure flow rate in open channels. In this study, flow rate calibration is experimentally investigated for an unsteady free flow. To consider the effect of flow rate on flow coefficient, increasing and decreasing flow rate regimes were considered. Experimental tests were performed in a laboratory flume equipped with real-time data acquisition and recording system. The behavior of the flow rate coefficient was investigated as a function of three dimensionless parameters containing weir height to the upstream water height ratio, the weir length to upstream water height ratio, and the weir width to upstream water height ratio. Results show that the flow rate coefficient is in reverse correspondence with all dimensionless parameters so that with an increase in each of these parameters, the flow rate coefficient decreases. Finally using genetic algorithm, the optimization of the flow rate coefficient was performed. It was shown that the calibrated flow rate coefficient lies between 0.4 and 0.7.


Main Subjects

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