Experimental Investigation of Sloping Sharp Crested Weirs in a 90-Degree Channel Bend

Despite the erosion and sedimentation and non-uniform flow distribution on both sides of the river that creates serious problems in exploitation processes، construction of diversion dams and weirs in river bend is unavoidable in some cases. The main hypothesis for more uniform distribution of flow across the bend width is equality of flow across the width of weir crest by change of weir crest profile from horizontal to sloping crest. This study describes the design theory of sloping sharp crested weir profile in a simple river bend، and the performance of sloping sharp crested weir in a 90-degree channel bend is evaluated with experimental works. The results showed that sloping sharp crested weirs are not appropriate in a straight reach and also in the start of the river bend. Sloping sharp crested weirs have satisfactory performance for channel bend. Appropriate slope of weir crest is evaluated in range of 80º<θ<85º. The results also showed that sloping sharp crested weirs have more uniform distribution of flow across the river bend width for weirs with shorter height (H=20 cm) and they work better in high flow rates (Q=75 L/s).