Acoustic Characteristics of Side Branch Silencers with a Finite Impedance at the End : Determination of the Peak Frequency of the Reduction Effect(Mechanical Systems)

Abstract

To improve the applicability of the side branch silencer, the acoustic characteristics of the side branch with finite impedance at the end were obtained by the experiment. As a result, the peak frequency of noise reduction (NR) was decided from the side branch length and the natural frequency of the end of side branch. Moreover, the experimental result was able to be caught by FEM analysis that considered 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 with one end open and the other end with impedance. Additionally, it has been understood that this is effective for the predictive calculation of the frequency at which NR is maximized.