Abstract
This paper deals with the characteristic of noise reduction of perforated-plug muffler with self generated flow noise. The perforated-plug muffler is a kind of reactive silencer, attenuating noise by a pipe with a closed end and a perforated surface inserted into an expansion chamber. It is widely used in various fields but its design method considering the self generated flow noise has not been cleared. The experiments were carried out by using low noise wind tunnel. It was cleared that arrangement of the pipe with the perforated-plug, that is downstream or upstream to the expansion chamber, affected not only the pressure loss but also the flow noise.
