Parametric study of helmholtz resonator performance and effect of poroacoustic material use in resonator design
Circular concentric Helmholtz Resonators have been extensively studied in various industries whereas Helmholtz resonators with normal incident configuration have not been theoretically, numerically or experimentally analyzed in sufficient depth. These resonators can offer useful acoustic design options when there are several constraints to be considered for example, space limitations, design specifications, materials available etc. For sound insulation on flat surfaces such as windows, Helmholtz Resonators (HRs) need to be normal to the sound pressure waves. This configuration is not extensively addressed in the literature. In this study, the effect of various design parameters such as neck radius, neck length, cavity radius and cavity length on sound transmission loss of HRs has been numerically analyzed and the results are discussed. This study also examines the effect of combining HRs in series and parallel network. Moreover, the effect of adding porous material lining is also explored using three different analysis modules of COMSOL, namely, pressure acoustics, solid mechanics, and poroelastic waves modules. Additionally, a theoretical one-dimensional model for side branch HRs is used to verify the numerical simulation, and the best design is introduced based on the results. Finally, the effect of structural vibrations on sound propagation properties of the system is analyzed and the results are discussed.