Bottom outlet conduits are the most important side constructions in dams which are used to control of reservoir water volume in back of dam, regulation of downstream water right and drain of the reservoir sediment. The Flushing operations to drain the reservoir sediments by high-speed flow in bottom outlet conduits of dams can create cavitation damages in these structures. Experiences showed that the flow aeration can decrease the risk of cavitation damages effectively. The investigations of flow characteristics by numerical methods along with physical hydraulic models can be effective in...