T. Herdtle, R. Gerdes, J.H. Alexander and J.S. Bolton, “Transfer impedance of microperforated materials with tapered holes,” Proceedings of INTER-NOISE 2011, 4448-4455, Osaka, Japan, Sept. 4-7, 2011.


Recently it was shown that relatively simple computational fluid dynamics models could be used to calculate the transfer impedances, including the associated end corrections, of microperforated panels. By using those procedures, Bolton and Kim in 2010 extended Maa’s classical theory to include a resistive end correction for sharp cylindrical holes which differs from those previously proposed. Here it is shown that CFD can additionally be used to compute these end corrections for tapered holes. Since practical experimental characterization of perforated materials often involves measurement of the static flow resistance, a closed form empirical equation for that quantity was developed. Finally, it is shown that configurations having equivalent static flow resistances can have different acoustic responses.


Microperforated panels, CFD, Transfer impedance, Tapered holes, End corrections


Acoustics and Noise Control

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