This paper is the second of two papers describing a method for modeling muffler components having perforated flow tubes, as for example those found frequently in automotive applications. In the first paper the theoretical model was developed, whereas here the theory is applied to demostrate specifically the utility and potential of the model. The applications are idealized in the sense that effects which occur simultaneously in perforated‐tube mufflers are treated separately. These effects are (1) the nonlinear impedance of the perforation due to finite amplitude sound pressure, and (2) the change in impedance of the perforation with mean flow. The first effect is demonstrated with a straight through resonator, and the second with a cross‐flow chamber. Predicted results for transmission loss in both cases compared quite well with measurements. Crucial to the success of the modeling was a proper description of the perforate impedance. The confidence instilled by the results prompted an inquiry into the nature of the two muffler components. It was determined by modeling that, contrary to popular opinion, these devices can be very dissipative, even though they contain no recognizable dissipative materials. The controlling mechanism is the high resistivity of the perforation induced by the acoustic/flow environment.

This content is only available via PDF.
You do not currently have access to this content.