抄録
The method of reduction of cavitation noise around a butterfly-valve is proposed and cavitating flow by numerical simulation is discussed. For the reduction of cavitation, a ditch was set up behind the valve. We experimented in the duct of circular cross section to confirm whether the method is effective. From the experimental result, it was confirmed that the ditch was effective for the reduction of cavitation noise in an actual pipe without losing the function of a butterfly-valve. Next the two-dimensional bubbly cavitating flow was analyzed by numerical simulation and it was confirmed that the bubble periodically grew up and collapsed near a comer of the wall.
