Multi-pass perforated tube silencers: A computational approach?

A time domain computational approach is applied to predict the acoustic performance of multiple pass silencers with perforated tube sections. This non-linear, one-dimensional method may readily include temporal and spatial variations in sound pressure level, orifice flow velocities, and mean duct flow, all of which affect the local orifice behaviour of perforated tube elements, and therefore the overall noise reduction characteristics. The transmission loss of two anechoically terminated multiple pass muffler configurations is determined computationally and experimentally for the limiting case of low sound pressure levels and zero mean flow. Comparisons between the numerical results and experimental data are shown to correlate well for frequencies where the one-dimensional assumption is justified. (C) 1998 Academic Press Limited.