On variation of absorption factor due to measurement method and correction factors for conversion between methods
2012 (English)In: 41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012, Volume 11, 2012, Institute of noise control engineering , 2012, 9343-9350 p.Conference paper (Other academic)
Sound absorbing materials are used in many applications to reduce sound, and their soundabsorbing characteristics are most often determined experimentally since theoreticaldetermination is difficult. Sound absorption factors are used in material specifications aswell as input to numerical simulations.Several methods for experimental determination of the absorption factor exist, two of themstandardized and frequently used. It is commonly known that the absorption factorobtained by these two methods differs as different sound fields are prescribed by thestandards. However, the size of the differences has not been so well described. Due to thisdifference, the choice of method is critical in order to avoid errors in simulations andspecifications of material properties.Experimental determination of absorption factors for three commonly used absorbers wasperformed, resulting in significant differences between the two methods. Correction factorsto compensate the absorption factor determined at one acoustic state and used in anotherare given. Theory verifying the differences is also presented.
Place, publisher, year, edition, pages
Institute of noise control engineering , 2012. 9343-9350 p.
Sound absorption coefficient, measurements
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-128557ScopusID: 2-s2.0-84883591764ISBN: 978-162748560-9OAI: oai:DiVA.org:kth-128557DiVA: diva2:648077
41st International Congress and Exposition on Noise Control Engineering 2012, INTER-NOISE 2012, New York, NY; United States; 19 August 2012 through 22 August 2012
References: Färm, A., Boij, S., Glav, R., On sound absorbing characteristics and suitable measurement methods (2012) Proceedings of the 7 International Styrian Noise, Vibration and Harshness Congress; (2003) Acoustics - Measurement of Sound Absorption in a Reverberation Room, , ISO 354; (1996) Acoustics - Determination of Sound Absorption Coefficient and Impedance in Impedance Tubes - Part 1: Method Using Standing Wave Ratio, , International standard ISO 10534-1; Delany, M.E., Bazley, E.N., Acoustic properties of fibrous absorbent materials (1970) Applied Acoustics, 3, pp. 105-116; Corcos, G.M., The structure of the turbulent pressure field in boundary layer flows J. of Fluid Mechanics, 18, p. 1964; Biot, M.A., Generalized theory of acoustic propagation in porous dissipative media (1962) Journal of the Acoustical Society of America, 34 (9), pp. 1254-1264; Attenborough, K., Acoustical characterization of porous materials (1982) Physics Reports, 82 (3), pp. 179-227; Sastry, J.S., Munjal, M.L., A transfer matrix approach for evaluation of the response of a multi-layer infinite plate to a two-dimensional pressure excitation (1995) Journal of Sound and Vibration, 182 (1), pp. 109-128
QC 201309132013-09-132013-09-132016-02-15Bibliographically approved