Jet noise modelling for shielding calculations using RANS solution source localisation and WEM propagation
2006 (English)In: 22nd International Conference on Noise and Vibration Engineering, ISMA, Leuven University Press, 2006, 667-676 p.Conference paper (Other academic)
In this paper, a method to determine the jet noise source input for shielding calculations is described. The method involves three steps - localisation, propagation and simplification. Firstly, for the frequency of interest, a small localised source region is determined, using Goldstein-Rosenbaum's acoustic model, with a numerical RANS solution providing local flow properties. A number of distinct incoherent noise sources may be located in this region, using the turbulence length scales. In the second step, each source is propagated out through the jet flow using the wave expansion method (WEM) to solve the Helmholtz equation, with local Mach values acquired from the RANS solution. The third step is to define a Kirchhoff surface outside the jet flow, from which the sound may be propagated further by simply using the Helmholtz-Kirchhoff integral, which can account for any mean flow present. Although the method is quite crude, it is relatively robust as it is a shielding factor or ratio, rather than an absolute value, which is of interest in design evaluation. Preliminary results, presented in this paper, provide encouragement that this new three-step jet noise source modelling method can be used to provide a source input for use in airframe shielding calculations, that is equivalent - in terms of source frequency, distribution and directivity - to the noise produced by a jet flow.
Place, publisher, year, edition, pages
Leuven University Press, 2006. 667-676 p.
Acoustic noise measurement, Navier Stokes equations, Shielding, Design evaluation, Incoherent noise, Modelling method, Shielding calculation, Shielding factor, Source frequency, Source localisation, Wave expansion methods
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-159532ISI: 000246669501007ScopusID: 2-s2.0-84897088514ISBN: 978-90-73802-83-4OAI: oai:DiVA.org:kth-159532DiVA: diva2:785478
International Conference on Noise and Vibration Engineering 2006, ISMA 2006, Heverlee, Belgium, 18 September 2006 through 20 September 2006
QC 201507062015-02-032015-02-032016-08-22Bibliographically approved