The effects of wedge geometrical parameters and arrangement on the sound absorption coefficient – A numerical and experimental study

M.E. Tavakkoli Nejad, A. Loghmani and S. Ziaei-Rad

Applied Acoustics, Volume 169, June 2020, Pages 107458

ABSTRACT

The design of sound-absorbing wedges as the main elements used in anechoic rooms is of great importance. There are general standards for the design of an anechoic room and sound-absorbing wedges. The absorption coefficients of the wedges can be obtained in two ways, a numerical technique such as the finite element method and an experimental test either in the impedance tube or in the reverberation chamber. In this paper, the absorption coefficient of a wedge covered by a perforated plate is obtained by simulating the 3D wedge in an impedance tube using COMSOL Multiphysics. To verify the finite element model, the perforated plate wedge is fabricated and tested in a real impedance tube based on ASTM C384. A comprehensive study is carried out on the effect of geometrical parameters on the sound absorption coefficient. These parameters include geometrical properties of the perforated plate such as hole diameter, hole percentage, plate thickness, and geometrical properties of the wedge, such as hub thickness, air gap thickness, wedge cross-section, and wedge width. Moreover, side wedges (semi wedges), the gap at sides of the wedges and lack of absorptive material in the wedge tip under the perforated panel are investigated. Finally, the effect of the arrangement of the wedges on the sound absorption coefficient is also studied.

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