Noise transmission control of double partition windows using T-shaped acoustic resonators

This paper presents theoretical and experimental noise transmission analyses on a double-partition window with structurally integrated T-shaped acoustic resonators. The study aims at providing a new and practical solution for the building and construction industry to tackle the ever-increasing noise pollution problems for residential areas locating near the airport and high traffic areas. Conventionally, grid-stiffened windows and double-partition windows are used to reduce the noise transmission into rooms. However, the use of grid-stiffeners embedded to glass panels will sacrifice window's vision quality and double-partition windows usually loose the noise insulation efficiency in the low-frequency range. Although classical Hemlholtz resonators may be used to improve the noise control performance of double-partition windows, this treatment is however not practical in such small enclosures due to the bubble-like profile of the Helmholtz resonator. The double-partition windows proposed in this paper incorporate long T-shaped acoustic resonators. The large aspect ratio of the long T-shaped acoustic resonator makes it possible to integrate the resonator into the sash of the windows, which relaxes the space requirement in implementation. A mathematical model describing structural and acoustic interaction between the glass panels, air cavity, and resonators is presented. Based on the model, the optimal location of the resonators is determined considering multiple cavity modes in addition to the targeted mode. Series of numerical simulations are conducted to illustrate the control of a specific resonance peak. The theoretical development provides insight into the noise transmission mechanism, leading to a helpful design tool for generating solutions to reduce the magnitude of noise transmission at cavity resonances, which currently still involve an effort of trial and error. Experimental measurements are also carried out, which are compared with the theoretical predictions.