Tailoring Plate Thickness of a Helmholtz Resonator for Improved Sound Attenuation

Abstract

A Helmholtz resonator with flexible plate attenuates noise in exhaust ducts, and the transmission loss function quantifies the amount of filtered noise at a desired frequency. In this work the transmission loss is maximized (optimized) by allowing the resonator end plate thickness to vary for two cases: 1) a nonoptimized baseline resonator, and 2) a resonator with a uniform flexible endplate that was previously optimized for transmission loss and resonator size. To accomplish this, receptance coupling techniques were used to couple a finite element model of a varying thickness resonator end plate to a mass-spring-damper model of the vibrating air mass in the resonator. Sequential quadratic programming was employed to complete a gradient based optimization search. By allowing the end plate thickness to vary, the transmission loss of the non-optimized baseline resonator was improved significantly, 28 percent. However, the transmission loss of the previously optimized resonator for transmission loss and resonator size showed minimal improvement.

Numerical and Experimental Analysis of Pressure Pulsation Attenuator Based on Helmholtz Resonator

“…The results show that the double-layer perforated liners can improve the damping in the higher frequency range. In 2016, Kurdi M. et al [15] changed the top of the cavity of the Helmholtz resonator into a uniformly flexible end plate. By optimizing and changing the thickness of the end plate, the transfer loss was increased by 28% compared to the previous.…”

Analytical modelling and experimental validation of compliance-based low-frequency resonators for water circuits

“…A single compact resonator has high transmission loss within a narrow frequency band around its resonance frequency, which can be tuned. By combining multiple compact resonators one can achieve high transmission losses in a broad frequency band [17][18][19][20].…”