Enhancement of sound absorber by multi-area Helmholtz resonators array based on Fibonacci sequence

This paper presents an innovative idea to the noise control problem for broader absorption bandwidth at low frequencies. For this aim, Helmholtz resonator array (HRA) designed based on Fibonacci sequence, which is addressed “Fibonacci based-HRA”. First, to validate the simulations which were performed through finite element method (FEM) as a numerical method in COMSOL Multi-physics software (Version 5.2), the results have been compared with experimental results which obtained by other researchers for two cases: (1) one unit resonator, and (2) four resonators array block with equal size. Second, to examine the performance of sound absorption of Fibonacci based-HRA, the results obtained for HRA with equal sizes of the 4, 6, 8 and 10 component resonators, compared with those obtained for Fibonacci based-HRA with the same number of the component resonators and the same overall dimensions of HRA block. The comparison showed that Fibonacci based-HRA approach is a good candidate for broad-band low frequency noise control.