気流を伴う音響管内しぼり部の音響的特性

抄録

This paper presents experimental investigation on acoustic characteristics of a contraction of area in a pipe with mean flow. Parameters describing the characteristics of the contraction are reflection coefficients of the inlet and outlet of the contraction and the transmission loss. These values are estimated from the experimental results comparing with calculated results. At first, fundamental parameters on the sound transmission in the pipe with mean flow, for instance, the viscothermal attenuation coefficient and the reflection coefficient at the open end of the pipe, are determined by experimental results of the standing waves in the pipe having the constant cross-section. And then, the acoustic parameters of the contraction are estimated by comparing the experimental results of the standing waves with the calculated results of these by numerical simulation of the reflection and the transmission coefficients at the inlet and the outlet of the contraction.