抄録
Perforated plates are often placed inside the muffler to reduce noise and enhance the strength of the muffler. However, the flow passing through the perforated plate would impinge on another inner plate and generate flow-induced noise. This study experimentally researched characteristics of the flow-induced noise generated by air flow passing through perforated plates and impinging on a flat plate. The perforated plate was installed at the end of the pipe through which steady air flow was supplied from a blower. The air flow passing through the perforated plate impinged on the flat plate. We examined effects of the hole diameter, dimensionless hole spacing, and distance between the perforated plate and the flat plate with constant total hole area and constant flow velocity at the hole. The results show that the flow-induced noise decreased with the increase in the distance between the perforated plate and the flat plate at frequencies higher than 100 Hz but increased at lower than 100 Hz.
