Experimental Study of Characteristics of Flow over Weirs with Semicircular Openings

In this research, an experimental investigation was conducted to study the characteristics of flow over weirs with semicircular openings. Four radii of the weir openings were used and three crest heights with either a sharp or semicircular shape for each radius. The results show that for the same crest height and the same depth of water over the crest, the discharge passing over the weir increased with the increasing radius of the semicircular opening. Also, for the same radius of the weir opening and the same depth of water over the crest, the discharge passing over the weir increased with the increasing crest height. For measuring the actual discharge over the weirs with semicircular openings, a new and reliable empirical equation was developed for the weirs with sharp crests and another one for weirs with semicircular crests.