FINITE-ELEMENT COMPUTATION OF ATTENUATION IN BAR-SILENCERS AND COMPARISON WITH MEASURED DATA

A finite element formulation for sound attenuation in ''bar-silencers' ', consisting of rectangular prisms of sound-absorbing material placed in a rectangular lattice arrangement within a rigid-walled duct, is d escribed. The presence of a uniform mean gas flow in the ''airway'' of the silencer is taken into account, as is anisotropy of the absorbent . Comparisons are made between experimental insertion less data and nu merical predictions, and generally reasonable agreement is noted. Comp arison is also made between the acoustic performance of bar-silencers and the equivalent splitter silencers, and it is shown that bar-silenc ers tend to have superior attenuation characteristics at low frequenci es. The present results are discussed in the context of previously pub lished work on bar-silencers. (C) 1996 Academic Press Limited