Paper Title
Investigating The Effect of Stepped Conduit and Vortex Blades In Dimensions on the Hydraulics of the Current Passing Over the Short-Throated Shaft Spillway

Abstract
This study examines the performance of a morning glory-type spillway equipped with vortex baffles and stepped conduit. Morning glory-type spillways are one such type of spillway that includes a separate channel that can replace the ancillary one. This spillway consists of a circular mouth, an orthogonal circular transform, and a horizontal (or nearly horizontal) pressurized tunnel that eventually transfers water from the dam reservoir to the downstream side. The results indicate that the pressure changes with the increase in the discharge rate and water height in the spillway with four steps, and the changes are small at lower discharge rates while very high-pressure changes have been documented for higher discharge rates. In some of the states, the pressure on the spillway's body is found to be intensely decreased. Based on the research, the best performance belongs to the morning glory-type spillway with 12 steps and four vortex breakers on the crest, as these configuration play an essential role in controlling the discharge rate and preventing cavitation. It is worth mentioning that the vortex breaker's dimensions based on the ratio of the vortex breaker's thickness (T) to the spillway's diameter (d) would not have an effect of more than 12.5% on the separation of the flow lines. The physical model used in the study is based on the spillway of the San Luis Dam in California, with modifications in dimensions and scale Keywords - Morning glory-type spillway, Stepped conduit, Spillover coefficient