Numerical Study on the Flow Pattern and Hydraulic Characteristics of Flow over Converging Spillway with Flip Bucket (Case Study: Gavshan Dam Spillway (

Spillways are one of the Most Important Hydraulic Structures of Dams that Transmitted Flood Entering the Reservoir with Sufficient Safety when Capacity Reservoir Completed. To Reduce the Cost of long Spillways and Topographic Factors, Walls, Especially in the Chutes Constructed. In this study, Flow over the Gavshan Dam Spillway Comprising Approach Channels, Ogee Crest, Converging Chute and Flip Bucket using Flow 3d Software and Turbulence Model K- , Simulated and Hydraulic Characteristics of Flow such as the Distribution of Velocity, Pressure, and Changes in the Depth is Studied. Comparing Numerical Results with Experimental Model Showed that there is not much difference between them. Changes in flow velocity over a spillway crest increase sudden and Rapidly and this Process Followed along Chute as far as most flow Velocity Rate in 1350 Cubic Meters per second, Equivalent to 30 meters per Seconds Accurate at the End of Chute (start of Flip Buckets) . 2/07 Degree Angle Convergent Walls are Optimized Angle to Prevent the Formation of Transverse Waves and Need to Increase the Height of the Walls of the Convergent Spillway.