Laboratory investigation on discharge coefficient of trapezoidal sharp crested side weirs

Side weirs are used in drainage systems, flood control, runoff collecting and many water resources and environmental projects. In this study, discharge coefficient in trapezoidal sharp crested side weirs was investigated by designing 18 weirs in subcritical condition and the effective factors on this parameter were studied. Some equations presented for calculating discharge coefficient with 4.3 and 5.4 percent error by using statistical methods and multiple regression. Results demonstrate that considering the side slope of the weir as an effective factor on discharge coefficient, increase accuracy of computations 1.2 up to 2.3 percent. Also, according to the calculations, the most important factor on discharge coefficient in this type of weirs is the ratio of overflow length to the length of the weir and omitting this factor leads to increase the error up to 1.4 percent.Side weirs are used in drainage systems, flood control, runoff collecting and many water resources and environmental projects. In this study, discharge coefficient in trapezoidal sharp crested side weirs was investigated by designing 18 weirs in subcritical condition and the effective factors on this parameter were studied. Some equations presented for calculating discharge coefficient with 4.3 and 5.4 percent error by using statistical methods and multiple regression. Results demonstrate that considering the side slope of the weir as an effective factor on discharge coefficient, increase accuracy of computations 1.2 up to 2.3 percent. Also, according to the calculations, the most important factor on discharge coefficient in this type of weirs is the ratio of overflow length to the length of the weir and omitting this factor leads to increase the error up to 1.4 percent.