Zahra Parhizkar - M.S. Student of Hydraulic Structures Engineering, Islamic Azad University, Science and Research Branch, Tehran
Amir Khosrojerdi - Associate Professor in Department of Water Science and Engineering, Islamic Azad University, Science and Research Branch, Tehran

Weather flow is studied in different fields of Engineering and Applied Science with different research and applied purposes. One use of weather flow research is to study the effect of this flow on dams’ spillways and lower drainage tunnels aimed at preventing the cavitation dangers, since aeration has been identified as one of the most economical and the most practical methods to deal with cavitation in spillways rapids. In the present study, the cavitation phenomenon and the effect of aeration systems in preventing this phenomenon on three dams of Iran were investigated through their physical model. They include spillways of Shafaroud, Azad and Gotvand dams. Based on results, using a single aeration system at Shafaroud dam spillway has had little effect on reducing the risks of cavitation. In the Azad dam spillway, using two aeration systems as the first option, and in the Gotvand dam spillway, using three aeration systems as the first and second choices in both channels have been the good options of aeration. According to the conducted studies, comparing the performance of aerator ramp in Azad and Gotvand dams led to acceptable results. Thus, in comparing the performance of aeration systems of these two dams spillway, we can say with lower(values of height to horizontal length ratio of the ramp (a/b), the maximum horizontal length of jet from the aerator ramp, chute angle and the height difference between the beginning and end of the spillway) and higher (height and horizontal length of the aerator ramp), the aeration efficiency will be better.

Chute spillways, cavitation, aeration