Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
On variation of absorption factor due to measurement method and correction factors for conversion between methods
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Flow acoustics. Acoustics department, Scania CV AB, Södertälje, Sweden.ORCID iD: 0000-0003-1604-8263
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. Acoustics department, Scania CV AB, Södertälje, Sweden.ORCID iD: 0000-0002-3826-3055
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.ORCID iD: 0000-0003-4103-0129
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, Published paper (Other academic)
Abstract [en]

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.
Keyword [en]
Sound absorption coefficient, measurements
National Category
Fluid Mechanics and Acoustics
Identifiers
URN: urn:nbn:se:kth:diva-128557Scopus ID: 2-s2.0-84883591764ISBN: 978-162748560-9 (print)OAI: oai:DiVA.org:kth-128557DiVA: diva2:648077
Conference
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
Note

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 20130913

Available from: 2013-09-13 Created: 2013-09-13 Last updated: 2016-02-15Bibliographically approved
In thesis
1. Analysis of Acoustic Absorption with Extended Liner Reaction and Grazing Flow
Open this publication in new window or tab >>Analysis of Acoustic Absorption with Extended Liner Reaction and Grazing Flow
2013 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Acoustic absorbing liners are efficient and commonly used measures to reduce sound levels in many fields of application. The sound reducingperformance of the liners is dependent on the acoustic state, defined by e.g. the flow and sound field interacting with the liner. To enable liner optimization the impact of these factors on the liner performance must be predictable. Studies of the impact of these factors were performed with existing experimental, analytical and numerical methods at low Mach number flows and material used in truck engine compartments. The study showed significant impact of both flow and sound field onthe liner performance. The size of the impact of the flow depends on which of the existing methods and models that was used, implying theneed of complementary methods. A new numerical method to model the boundary layer effect was for this reason developed in this work. The method was shown to predict the impact of flow correctly compared to the Pridmore-Brown solution and the method was computationally efficient. The sound reducing performance of a liner exposed to complex sound field and grazing flow can be predicted using existing methods together with the new proposed method. Extra care has to be taken when bulk reacting liners are considered since additional complications compared to locally reacting surfaces occur in presence the of grazing flow.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2013. x, 46 p.
Series
Trita-AVE, ISSN 1651-7660 ; 2013:42
Keyword
Sound absorption, acoustic lining, non-locally reacting, boundary layer, grazing flow, sound field, transfer matrix method
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-128711 (URN)
Presentation
2013-09-27, K2, Teknikringen 28, KTH, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

QC 20130916

Available from: 2013-09-16 Created: 2013-09-16 Last updated: 2013-09-16Bibliographically approved

Open Access in DiVA

afarm_Internoise2012(299 kB)264 downloads
File information
File name FULLTEXT01.pdfFile size 299 kBChecksum SHA-512
6cc45140ecaf09ffa4327315bbd7597dd821c637cf68a9ebefdc67035f2f4128c00d573186735d199b8042170f8f96fea5872e28c4abe05289200c37e24c94e2
Type fulltextMimetype application/pdf

Other links

ScopusInternoise2012

Search in DiVA

By author/editor
Färm, AnnaGlav, RagnarBoij, Susann
By organisation
MWL Flow acousticsMarcus Wallenberg Laboratory MWLAeronautical and Vehicle Engineering
Fluid Mechanics and Acoustics

Search outside of DiVA

GoogleGoogle Scholar
Total: 264 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 86 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf