Document Type : Original Article
Department of Civil Engineering, Engineering Faculty, Islamic Azad University, Sepidan Branch, Sepidan, Iran.
Knowing more about the flow behavior of short-stepped shaft spillways helps to use this structure better and more efficiently. Moreover, using a vortex breaker greatly affects passing flow through Shaft Spillway. For use more efficiently, the risk of the flow of water on the crest decreases to less than fluid vapor. The water head on the crest, called cavitation, should be prevented as long as possible. This research has tried to experimentally study different behaviors of stepped chambers and different vortex breaker shapes on spillway flow. From the viewpoint of the effects of flow regime changes on spillways, changes according to the vortex breaker shapes, and the change of type of flow range will be studied effectively. Finally, the best relationship between the water head on the crest and the discharge coefficient was determined. One of the most important issues on the hydraulic coefficient of the spillway is related to the relationship between the water head on the crest and the hydraulic coefficient of this special hydraulic structure. In other words, when flow changes and moves upward till full pipe condition, knowing about the empirical coefficient of the spillway is very useful to predict hydraulic behavior in different situations.