Experimental investigation of perforations interactions effects under high sound pressure levels

TL;DR

This study experimentally examines how perforation interactions affect acoustic absorption in perforated panels under high sound pressure levels, revealing that proper hole configuration can optimize sound absorption even with interactions.

Contribution

It provides new experimental data on perforation interactions at high sound levels, extending existing models to include these effects for better panel design.

Findings

HIE effects are significant at high sound levels.

Proper hole configuration enhances sound absorption.

Nonlinear reactance dependency remains slight despite interactions.

Abstract

Most models for predicting the acoustic response of perforated panels are based on the assumption that there is no interactions between the holes. The common way of taking into account the perforates effects is the use of Fok's functions. The few papers that deal with these effects study the case of low sound pressure levels. This paper investigates the Holes Interaction Effects (HIE) of perforated and micro-perforated panels when submitted to high sound pressure levels. Analysis of the data yields to the fact that even with HIE, the nonlinear reactance dependency with velocity is very slight. The HIE can provide good absorption of the perforated panel backed by an air cavity at low and high sound pressure levels if the holes positions are well configured. Perforated panels of holes diameters less than 2 millimeters were built out of steel with different interstices (distance between two adjacent holes) and tested. Experimental results (performed with an impedance tube) in the cases of interaction are done and compared with the exact cases of no interactions. The results can be used for designing optimal perforated panels for ducts silencers for instance.