بررسی آزمایشگاهی تاثیر شکل تیغه های ضد گرداب بر راندمان تخلیه ی سرریزهای نیلوفری

where there is not adequate space to build other types of spillways, morning glory spillways are use to pass the excess water from the headwater to the dam downstream. Creation of strong vortices in the entrance is among the main problems faced with these types of spillways. One of the effective methods of controlling the vortex is using the vortex breaker blades, which are used in this spillway to increase the discharge rate and coefficient. In this paper, the physical model was constructed and the effect of shapes triangular, rectangular and baleen body of anti-vortex blades on the discharge coefficient of the morning glory spillway was examined by conducting ۹۱ experiments. The results showed that the baleen shape of vortex breaker blade has the greatest impact on increasing the efficiency of the spillway discharge coefficient. The results indicate that the airfoil type anti vortex blade in contrast to rectangular and triangular type have a greater effect on increasing the discharge efficiency in a way that in the best condition (L/D=۰.۲۵) and the constant submerged ratio (H/R=cte), airfoil type, rectangular and triangular increased the discharge coefficient by ۵۲, ۳۹ and ۳۲ percent respectively.