Abstract
In this paper four gate openings and fifteen operating scenarios in terms of the difference in the arrangement of working gates were studied. The Expansion Ratio (e) which is (the ratio of total width of the channel to the total width of the working gates) was calculated for each scenario. It can be seen that when the value of (e) was the largest possible, which is (5.34), the value of the discharge coefficient (Cd) was also as high as possible, reached to (0.845). Also, the value of the contraction coefficient (Cc) was the highest value, (0.693). The increasing in the value of (e) means that the number of openings that work is less. Both (Cd) and (Cc) are decreases when Froude Number increased for all scenarios of gate worked operations.
