Theoretical and experimental study on effect of melamine foam lining on acoustic characteristics of a cylindrical cavity

Abstract

In this study, great efforts were paid to investigate noise reduction in a cylindrical cavity with melamine foam (MF) lining within the low-medium frequency range (100–400 Hz). In theoretical studies, MF was generally regarded as the impedance boundary according to the Johnson-Champoux-Allard (JCA) model. In this context, natural frequencies of the cylindrical cavity with presence of locally and non-locally reacting liners were derived from theories of the cylindrical cavity lining. Moreover, noise experiments were conducted in the cylindrical cavity with and without MF lining, which were consistent with the theoretical results and demonstrated the higher reliability in the condition with non-locally reacting liner. Furthermore, the natural frequency of the cylindrical cavity declined after MF lining was introduced, and the declining degree was found to be proportional to the thickness of MF lining. Eventually, it was demonstrated that MF lining could achieve noise reduction by up to 4–8 dB within the low and medium-frequency range. Keywords: Cylindrical cavity, Melamine foam (MF), Natural frequency, Noise attenuation