Affiliations: Institut Teknologi Bandung, Bandung, Indonesia. | University of Kentucky, Lexington, Kentucky,
USA.
Abstract: This paper presents a prediction technique for wave propagation in
muffler using Boundary Element Method (BEM). The results of the numerical
calculation are compared with the plane-wave theory and also the experimental
results. It is shown that at high frequencies the plane-wave theory does not
yield correct results due to the occurrence of two- and three-dimensional wave
motion. On the other hand, the BEM is able to predict the acoustic wave
behavior in the high frequencies where the plane-wave theory fails. The BEM
uses a multi-domain technique to model complex mufflers, which may consist of
cavities, tubes, perforates, and porous materials. Contour plots of sound
pressure level inside the mufflers obtained from the BEM results are used to
illustrate the principle of sound cancellation and to visualize the wave
propagation behavior.