Experimental investigation of the acoustic effect of non-rigid walls in IC-engine intake systems
2006 (English)In: International Congress on Sound and Vibration 2006, ICSV 2006 / [ed] J. Eberhardsteiner, H.A. Mang, H. Waubke, 2006, 1097-1104 p.Conference paper (Refereed)
This paper presents the results of an experimental study of the acoustic properties of an automotive air intake system. Modern air intake systems for personal cars are largely made of plastic materials. When trying to make an acoustic model for the sound transmission through the intake system it is questionable if the walls of different components can be modelled as acoustically rigid. The acoustic losses which determine the transmitted sound level at breakthrough frequencies may be especially difficult to model. To find out if acoustic losses associated with wall vibrations or with flow interaction are dominating for a typical intake system an experimental investigation has been performed. The acoustic plane-wave transmission matrices have been measured, using the two-source replacement technique, for the complete intake system and for separate parts. Measurements were made in a flow test rig without flow and for two different flow speeds. The measurements were then repeated with sand loading on the walls to reduce wall vibrations. The results indicate that flow related losses dominates at low frequencies while losses associated with acoustically non-rigid walls dominate at higher frequencies, giving an additional transmission loss in the order of 2 dB for the complete system. Both effects will therefore have to be taken into account in an accurate model. Comparisons will also be made between results from an acoustic FE-model and experimental results.
Place, publisher, year, edition, pages
2006. 1097-1104 p.
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-26056ScopusID: 2-s2.0-84883409090ISBN: 978-162748150-2OAI: oai:DiVA.org:kth-26056DiVA: diva2:369457
ICSV13-Vienna, The Thirteenth International Congress on Sound and Vibration, Vienna , Austria, July 2-6, 2006
QC 201011102010-11-102010-11-102014-11-17Bibliographically approved