Experimental Investigation on Acoustic Characteristics of Segmented Local-Reacting Liner

Two candidate liners, one was single-DOF uniform liner and the other was two-zone segmented liner, were manufactured with 3D printing technology. Liners were separately tested under the condition of grazing velocity of maximum Ma=0.3 and incident sound pressure level of 130dB on flow acoustic tube....

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Bibliographic Details
Main Authors: Yang, Jiafeng, Yan, Qun, Xue, Dongwen, Li, Zhuohan
Format: Conference Proceeding
Language:English
Subjects:
Absorption
acoustic impedance
Acoustics
Attenuation
Boundary conditions
Loss measurement
nacelle
Propagation losses
segmented liner
straightforward method
Three-dimensional printing
transmission loss
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Summary:Two candidate liners, one was single-DOF uniform liner and the other was two-zone segmented liner, were manufactured with 3D printing technology. Liners were separately tested under the condition of grazing velocity of maximum Ma=0.3 and incident sound pressure level of 130dB on flow acoustic tube. The straight-forward method (SFM) and Prony analysis were employed to educe the acoustic impedance of the liner as well as the two-microphone was carried to decompose the standing waves to determine the Transmission Loss (TL) of the liner-installed section, after which the measured data were compared and the reason why the acoustic resistance is obviously larger at some frequency was analyzed. Initial results show that segmented liner of the same size is favorable to broaden the sound absorption frequency band and is suitable to control multi-tone noise, but the TL peak turns to be weaker. In flow acoustic tube, when only plane waves incident at low grazing velocity, the laying order of each parts of segmented liner dose not affect the overall noise attenuation, but when grazing velocity gets higher, it will pose changes on peak frequency and peak TL of segmented liner. A sufficient sound attenuation is required to ensure the accuracy of tested result as Myers-Ingard boundary condition is used to calculate wall's acoustic impedance.
ISSN:2770-792X
DOI:10.1109/ICICSP55539.2022.10050713