Computation of discharge for simultaneous flow over weirs and below gates (H-weirs)

Simultaneous flow over weirs and below gates for free flow condition is experimentally investigated. Combination of a sharp-crested rectangular weir and rectangular gate is considered as a flow measurement structure which is named as H-weirs. H-weirs are defined by the width of the weir and gate openings, the height of the gate opening and the vertical distance between bottom of the weir and top of the gate. Laboratory experiments are conducted by measuring the discharge and the depth of water at upstream for different H-weirs. The present study aims to determine the discharge for a given H-weir simply by reading the depth of water at upstream of the combined structure. The compatibility of various formulations of the discharge–depth of water relationship is investigated by using the collected data and two new formulations are suggested based on the analysis of these data. After obtaining and comparing percentage errors of each equation, it is concluded that the new proposed equations can be used to accurately predict the discharge through H-weirs within the given ranges of the experimental study.

► An experimental study was conducted with increased range of data limits for H-weirs.
► After performing overall optimization, it was found that Fr was functions of H/y and y/d.
► We proposed new explicit equations to accurately predict the discharge–water depth relationship for H-weirs.