Polyharmonic Distortion Modelling Applied to Acoustic Characterisation of Peforates

This paper discusses the possibility to apply polyharmonic distortion modelling, used for nonlinear characterisation of microwave systems, to acoustic characterisation of samples with non-linear properties such as perforates and other facing sheets used in aircraft engine liners and automotive mufflers. In some previous papers multi-port techniques using sinusoidal excitation for characterization of samples with non-linear properties were developed and experimentally tested. These techniques aimed at taking non-linear energy transfer between sound field harmonics into account. Essentially linear system identification theory was however used assuming that superposition applies and that the functions studied are analytical. Polyharmonic distortion modelling does not assume that the function relating waves incident and reflected or transmitted is analytic nor does it assume application of normal superposition. This technique is tested on experimental data obtained from measurements on a perforate mounted in a duct. The similarity to the previously developed nonlinear scattering matrix techniques is demonstrated. It is shown how the results obtained can be used to analyse nonlinear energy transfer to higher harmonics. © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

[1]  Christopher K. W. Tam,et al.  A NUMERICAL AND EXPERIMENTAL INVESTIGATION OF THE DISSIPATION MECHANISMS OF RESONANT ACOUSTIC LINERS , 2001 .

[2]  Hans Bodén,et al.  On Semi-Empirical Liner Impedance Modeling with Grazing Flow , 2003 .

[3]  Uno Ingard.  Nonlinear Distortion of Sound Transmitted through an Orifice , 1970 .

[4]  Hans Bodén.  On Impedance Measurements for Samples with Non-linear Acoustic Properties , 2008 .

[5]  Christopher K. W. Tam,et al.  Micro-fluid dynamics and acoustics of resonant liners , 1999 .

[6]  Christopher K. W. Tam,et al.  Microfluid Dynamics and Acoustics of Resonant Liners , 2000 .

[7]  D. A. Blaser,et al.  Transfer function method of measuring in-duct acoustic properties. I - Theory. II - Experiment , 1980 .

[8]  Mats Åbom,et al.  Error analysis of two‐microphone measurements in ducts with flow , 1988 .

[9]  U. Lott.  Measurement of magnitude and phase of harmonics generated in nonlinear microwave two-ports , 1989 .

[10]  F. Saybert,et al.  Experimental determination of acoustic properties using a two-microphone random-excitation technique * , 2004 .

[11]  T. H. Melling,et al.  The acoustic impendance of perforates at medium and high sound pressure levels , 1973 .

[13]  J. Verspecht,et al.  Large-signal network analysis , 2005, IEEE Microwave Magazine.

[14]  U. Ingard,et al.  Acoustic Circulation Effects and the Nonlinear Impedance of Orifices , 1950 .

[15]  D.E. Root,et al.  Polyharmonic distortion modeling , 2006, IEEE Microwave Magazine.

[16]  Hans Bodén,et al.  Acoustic characterisation of perforates using non-linear system identification techniques , 2007 .

[17]  Mats Åbom,et al.  Influence of errors on the two‐microphone method for measuring acoustic properties in ducts , 1986 .

[18]  Hans Bodén.  Multi-port techniques for acoustic characterisation of non-linear in-duct discontinuities , 2009 .

[19]  Hans Bodén,et al.  Linearity tests for in-duct acoustic one-port sources , 2000 .

[20]  Hans Bodén.  Experimental Investigation of Harmonic Interaction Effects for Perforates , 2005 .

[21]  Mats Åbom,et al.  Measurement of the scattering-matrix of acoustical two-ports , 1991 .

[22]  Kari Lehtinen,et al.  High-frequency periodic time-domain waveform measurement system , 1988 .

[23]  U. Ingard,et al.  Acoustic Nonlinearity of an Orifice , 1967 .

[24]  Hans Bodén,et al.  Experimental Investigation of Nonlinear Acoustic Properties for Perforates , 2006 .

[25]  A. Barel,et al.  Accurate on wafer measurement of phase and amplitude of the spectral components of incident and scattered voltage waves at the signal ports of a nonlinear microwave device , 1995, Proceedings of 1995 IEEE MTT-S International Microwave Symposium.