One-way fluid-to-acoustic coupling approach for acoustic attenuation predictions of perforated silencers with non-uniform flow

Abstract

A one-way fluid-to-acoustic coupling approach which combines the computational fluid dynamics and the acoustic finite element method is employed to predict the acoustic attenuation performance of perforated silencers in the presence of non-uniform flow. This technique ensures that the convective and dissipative effects caused by fluid flow on the acoustic attenuation performance of perforated silencer can be taken into account. The comparisons between the numerical predictions and the previously published experimental measurements show the reasonably good agreements. The acoustic attenuation predictions of perforated silencers without and with flow show that (1) the effect of grazing flow on the acoustic attenuation of the straight-through perforated tube silencer is obvious at higher frequencies, while marginal in the low frequency range; (2) the bias flow enhances the acoustic attenuation performance of perforated silencers at most frequencies; (3) the grazing-bias flow reduces seriously the first resonant peak of three-pass perforated tube silencer and increases the acoustic attenuation in specific frequency range; and (4) when the grazing-bias flow in the orifices of perforated tube and bias flow in the orifices of perforated bulkheads exist simultaneously, the latter plays a leading role to the acoustic attenuation performance of three-pass perforated silencers.