In this work, a finite element approach is presented for modelling sound propagation in perforated dissipative mufflers with non-homogeneous properties. The spatial variations of the acoustic properties can arise, for example, from uneven filling processes during manufacture and degradation associated with the flow of soot particles within the absorbent material. First, the finite element metho...

This paper reviews recent developments in the application of the boundary element method (BEM) to muffler and silencer analysis. Initial results of modeling built-in catalyst converters are also presented. A so-called “direct mixed-body boundary element method” has been developed for muffler and silencer analysis since 1996. The idea of the method is to integrate all kinds of different boundary...

In recent years, when consumers buy home appliances and cars, energy efficiency has been considered to be significant. Therefore, studies on how to increase the energy efficiency are being accelerated. A representative study is to raise the energy efficiency of the compressor which is a core part of the refrigerator using acoustic theory in suction part. However, the acoustic source characteris...

Automotive exhaust systems give a major contribution to the sound quality of a vehicle and must be properly designed in order to produce acceptable acoustic performances. Obviously, noise attenuation is strictly related to the internal gas-dynamic field that, on the other hand, needs to be optimised also in terms of pressure losses. In this work, the noise attenuation characteristics of a perfo...

background and aims: since using city power for welding process is not allowed, diesel generators are used as a power supply in construction industries. they could be introduced as a main source of noise pollution. the purposes of this study were to assess and control noise pollution produced by construction diesel generators in hamadan, iran. methods: in this descriptive, cross-sectional study...