# Performance of Reactive Acoustic Mufflers

Performance of Reactive Acoustic Mufflers

This Demonstration represents analytical, closed-form solutions for the transmission loss of two common reactive mufflers, an expansion chamber and a quarter-wave resonator. These closed-form solutions are assumed to be accurate only at low frequency where only plane waves are involved. The analytical models were derived using continuity conditions at each change of cross-sectional area [1]. The analytical models assume rigidity.

Muffler performance determined by transmission loss is governed by the cross-sectional area ratio of expansion chamber to pipe , the cross-sectional area ratio of quarter-wave resonator to pipe , wavenumber , and muffler length . As ratios and increase, the performance of each respective muffler improves. Resonances and anti-resonances are also clearly recognizable. A comparison plot is also presented in order to give the reader a generalized idea about muffler performance of a combined expansion chamber/quarter-wave resonator.

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