Abstract
To improve the applicability of the side branch silencer, the acoustic characteristics of the side branch with a finite impedance at the end was obtained by the experiment. As a result, it was clarified that the peak frequency of the noise reduction (NR) could be decided from the side branch length and the natural frequency of the end of a side branch. Moreover, the experimental result is in good agreement with the analysis of FEM considering the theoretical impedance of the circular membrane and the theoretical calculation by the transfer matrix method. In addition, it has been understood that the peak frequency of NR in this side branch corresponds to the natural frequency of a simple tube of the one open end and the other end with an impedance. Additionally, it was understood that the calculation of the natural frequency of the simple tube is effective for the prediction of the frequency at which NR becomes maximum.
