Momentum Model of Flow Past Weir

Circular-crested weirs are used for flow measurement and have wide applications in irrigation systems, where they serve as overflow structures. For flow past such a weir, the discharge coefficient was obtained on the basis of momentum analysis. Tests were conducted over a wide range of geometric and hydrodynamic variables characterizing the weir flow. The pressure distributions at various vertical sections and the depth of flow at the crest section were obtained for the flow over the weir. The discharge coefficient determined on the basis of momentum analysis is compared with results obtained from direct measurement of the discharge.