Transfer impedance of microperforated materials with tapered holes

• DOI: 10.1121/1.4824968
• Publication Date: 2013-12-09T23:18:15Z
• Authors: Thomas Herdtle; J. Stuart Bolton; Nicholas N. Kim; Jonathan H. Alexa...; Ronald W. Gerdes
• Keywords: Resistive touchscreen

It has been previously shown that relatively simple computational fluid dynamics (CFD) models can be used to calculate the transfer impedances, including associated end corrections, of microperforated panels. The impedance is estimated by first calculating pressure difference across a single hole when transient input velocity imposed, and then Fourier transforming result obtain as function frequency. Since size dimensions inlet outlet channels are very small compared wavelength, flow through modeled incompressible. By using those procedures, Bolton Kim extended Maa's classical theory include resistive correction for sharp-edged cylindrical holes which differs from proposed inclusion static component. Here it CFD also compute corrections tapered holes. practical experimental characterization perforated materials often involves measurement resistance, closed form empirical equation quantity developed. Finally, configurations having equivalent resistances yield different acoustic absorptions.