Analysis of the impact of effective length of morning glory spillway on its performance (numerical study)

Abstract

The Morning Glory spillway is one of the types of spillways that are used for the passage of excess waters and floods from the dams' upstream to the downstream of the dams. Numerical simulations and examination have been rarely done on the sectoral Morning Glory spillways, which are used due to special conditions in the topography of the construction site. In this research, the simulation of the flow through the sectoral morning glory spillway was done using the three-dimensional numerical model. The characteristics of flow in this type of spillways were investigated and a relation was proposed for the rate of water discharge. To do this, five sector angles were considered in the geometry of the spillway crest and the characteristics of the flow, as well as the amount of drainage capacity in them were compared. Finally, a relation was provided to calculate the discharge flow rate of the sectoral morning glory spillways. The results obtained from the relation indicated that the maximum error of the calculations with the help of the relation provided is equal to 7.77 % and occurs at a sector of 62 degrees. This error percentage confirms the reliability of the relation.