Enhancement of Low-Frequency Noise for Muffler by Optimizing the Space between Three 1-Degrees of Freedom Helmholtz Resonator

Abstract

The Helmholtz resonator is one of the basic elements to attenuate low-frequency noise and increase sound transmission loss in a muffler for particular low frequency zone. It can be enhancing the performance without any change in the geometry of the muffler. It can greatly reduce the high-intensity noise in low-frequency zones. A comparative study has been carried out by implementing the two and three resonators arranged in series arrangement at optimum spacing for increasing transmission loss. The model of Helmholtz resonator at wavelength 1000 mm at different spacing like (closely spaced: -(4), 1stantinode: -(4) and 1st node: -(2) ) were prepared by using wave build 3-D and simulating above condition on wave 1-D module. This work is also validated by simulating the same geometry on Comsol tool for the mentioned spacing. This attempt gives a comparative study about perfect spacing during use of more than one resonator in a series. The neck and cavity ratio are taken as 2 and 1.85 respectively for the modelling of an identical resonator. The Conclusion shows that, at (4) resonator gives the maximum attenuation at 340 Hz cut-off frequency in low-frequency zone.