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
Nonlinear Properties of Acoustic Liners Under High Level Random Excitation in Combination with Single-Tone Excitation
KTH, School of Engineering Sciences (SCI).
2017 (English)Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
Abstract [en]

With the increase in air travels the last decades the number of airplanes have increased dramatically. The sound generated by the engines have become a significant problem. The last 60 years a lot has been made trying to reduce the noise levels. Modern jet-engines generates a combination of broadband random noise and tonal components. Acoustic liners are commonly used sound attenuators in jet-engines. Research has shown that acoustic liners can behave both linearly and nonlinearly depending on the sound pressure level.

Many studies on the nonlinear effects of acoustic liners have been made and in this report the effect of high level broadband excitation in combination with tonal excitation is evaluated. If nonlinear effect occur it can be of importance for future construction of sound attenuators for jet-engines.

The result from this study indicates that at high levels of excitation there is a nonlinear relationship between the random excitation and the tonal excitation. High levels of tonal excitation can increase the level of the random excitation over the full frequency range. For high levels of random excitation the level at the excited tone decreased. Even random excitation at lower frequencies than of the tone can have an effect at the tonal frequency.

Place, publisher, year, edition, pages
2017. , 35 p.
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:kth:diva-211562OAI: oai:DiVA.org:kth-211562DiVA: diva2:1130070
Supervisors
Examiners
Available from: 2017-08-08 Created: 2017-08-08 Last updated: 2017-08-08Bibliographically approved

Open Access in DiVA

fulltext(4050 kB)19 downloads
File information
File name FULLTEXT01.pdfFile size 4050 kBChecksum SHA-512
8afa6e8716aa46a9d2cfe66440860e18cbc9ee7b1405671d96351e453630f0a83b03f70ab8086888c76639ef3931e794172bb895ddb3f03747e371ad42547364
Type fulltextMimetype application/pdf

By organisation
School of Engineering Sciences (SCI)
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 19 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

urn-nbn

Altmetric score

urn-nbn
Total: 49 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