Acoustic impedance of micro-perforated panels in a grazing flow

Xiaoqi Zhang, Li Cheng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

19 Citations (Scopus)


Micro-perforated panels (MPPs) are widely used for broadband sound absorptions. For a MPP exposed to a grazing flow, existing acoustic impedance formulas based on different flow parameters give inconsistent results, thus calling for a systematic investigation of the issue to find more intrinsic flow parameters allowing for a reliable acoustic impedance prediction. In this study, three-dimensional CFD simulations are conducted on a MPP hole with a backing space in a flow duct. Numerical results allow identifying the flow velocity gradient in the viscous sublayer as the intrinsic flow parameter and show its linear relationship with a flow-related term in the acoustic resistance formula. Through a linear regression analysis, an acoustic resistance formula is established within a certain flow range (Mach number up to 0.25) under the linear acoustic regime. The validity of the impedance formula is demonstrated through comparisons with existing results and experimental data reported in the literature, showing good agreement and superiority in terms of the prediction accuracy.

Original languageEnglish
Pages (from-to)2461-2469
Number of pages9
JournalJournal of the Acoustical Society of America
Issue number4
Publication statusPublished - 1 Apr 2019

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Acoustics and Ultrasonics


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