A STUDY OF SPATIAL VARIATION OF DISCHARGE COEFFICIENT IN BROAD-CRESTED INCLINED SIDE WEIRS

The side weir is a hydraulic structure that is widely used in irrigation and drainage networks and water treatment plants. To estimate the outflow over a rectangular broad-crested side weir, the discharge coefficient in the side weir equation needs to be determined. In this study, a comprehensive laboratory study including 240 tests was conducted in a physical model under subcritical flow conditions. The variation of discharge coefficient along the side weir was investigated in relation to height, width and slope of side weir. Furthermore the data of experimental tests were statistically analysed. As a result, a mathematical model for computation of the spatial discharge coefficient is presented in this study. The presented mathematical model enables accurate estimation of discharge coefficient along the side weir when compared with the measured data under subcritical flow conditions. Additionally, in comparison with overall discharge coefficient models, the developed model estimates a relatively accurate spatial discharge coefficient for the side weir. Additionally, to equalize the flow depth alone, the side weir, some relationships were proposed in this paper. Copyright (C) 2008 John Wiley & Sons, Ltd.