The effect of high level multi-tone excitation on the acoustic properties of perforates and liner samples
2012 (English)In: 18th AIAA/CEAS Aeroacoustics Conf. (33rd AIAA Aeroacoustics Conf.), American Institute of Aeronautics and Astronautics, 2012Conference paper (Refereed)
This paper discusses the effect of high level multi-tone acoustic excitation on the acoustic properties of perforates and liner samples. It is based on a large experimental study of the nonlinear properties of these types of samples without mean grazing or bias flow. It is known from previous studies that high level acoustic excitation at one frequency will change the acoustic impedance of perforates at other frequencies, thereby changing the boundary condition seen by the acoustic waves. This effect could be used to change the impedance boundary conditions and for instance increase the absorption. It could obviously also pose a problem for the correct modelling of sound transmission through ducts lined with such impedance surfaces. First a quasi-stationary model for the acoustic properties of the perforate is discussed and the results are compared to experimental data. The effect of the combination of frequency components in the excitation signal is studied to find out if it matters if we are using tones which are harmonically related or not. The effect the phase of the frequency components is studied using both the model and experimental data. It is also discussed if a parameter controlling the impedance can be found for an arbitrary combination of tones with different frequencies.
Place, publisher, year, edition, pages
American Institute of Aeronautics and Astronautics, 2012.
Acoustic excitation, Different frequency, Experimental datum, Experimental studies, Frequency components, Impedance boundary conditions, Nonlinear properties, Sound transmission, Acoustic impedance, Acoustic wave transmission, Boundary conditions, Aeroacoustics
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-129811DOI: 10.2514/6.2012-2151ScopusID: 2-s2.0-84880608710ISBN: 978-160086932-7OAI: oai:DiVA.org:kth-129811DiVA: diva2:653903
18th AIAA/CEAS Aeroacoustics Conference 2012 (33rd AIAA Aeroacoustics Conference),4 June 2012 through 6 June 2012