Noise attenuation performance of multiple helmholtz resonator arrays system

This paper focuses on improving the noise attenuation performance of a ducted Helmholtz resonator (HR) arrays system. The noise attenuation performance achieved by the HR system is fairly depended on the number of HRs, which is limited by the available space for HR's installation. Two cases are investigated: the periodic ducted HR system and the multiple HR arrays system. The multiple HR arrays system is based on the periodic system by adding identical resonators on the cross-section. Several identical resonators mounted on the same cross-section is considered as one unit in the system, the resonance frequency of the unit is the same as a single resonator. The transfer matrix method and the Bragg theory are used to investigate the wave propagation in the multiple HR array system and the periodic ducted HR system theoretically. The theoretical prediction results fit well with the Finite Element Method (FEM) simulation results. The results show that different arrangement of the HRs mounted on the duct has no effect on the TL once the number of HRs and the periodic distance are both the same. The proposed multiple HR array system has potential application in noise control with space limitation.