A discharge coefficient for a trapezoidal broad-crested side weir in subcritical flow

An experimental investigation of the flow over trapezoidal broad-crested side weir in rectangular channels under subcritical flow conditions is reported. It was found that the discharge coefficient of a trapezoidal broad-crested side weir is related to the Froude number at the upstream of the weir, ratios of weir height to depth of flow, weir length to width of main channel and length of broad-crested weir to width of main channel for different side slopes. Additionally, a reliable equation for calculating the discharge coefficient of trapezoidal broad-crested side weirs is presented.

► The discharge over the trapezoidal broad-crested side weir is measured.
► We proposed new equation for the discharge coefficient in the trapezoidal broad-crested side weir.
► Four dimensionless parameters are obtained using dimensional analysis for the discharge coefficient.