An investigation into the effects of engine body reflections and flow refraction on jet noise shielding predictions
2007 (English)In: 36th International Congress and Exhibition on Noise Control Engineering, INTER-NOISE, 2007, Vol. 2, 733-742 p.Conference paper (Other academic)
Airframe acoustic shielding predictions, using simple point sources located over an isolated wing, tend to over-predict shielding effects, when compared with full-model test data. The study presented in this paper investigates the effects of the inclusion of the engine body and the jet flow on shielding predictions. A wave expansion method (WEM), is used to efficiently model the sound propagation, in a small domain which includes the wing and engine body. In this model the jet is still represented as point sources. A 2d model is examined, in which the mean jet flow has been included. The point source locations and strengths are determined using a RANS solution of a hot coaxial jet and Goldstein's interpretation of the acoustic analogy. The near-field WEM results are then propagated to the far-field using the Helmholtz-Kirchhoff integral equation, which assumes a uniform flow external to the Kirchhoff surface. Results presented here are very encouraging as they clearly indicate that with the inclusion of engine body reflections, and the refractive effects of the jet flow, predicted shielding values are much more consistent with observed levels both in terms of magnitude and variation over observation angle.
Place, publisher, year, edition, pages
2007. Vol. 2, 733-742 p.
Acoustic noise, Acoustic wave propagation, Exhibitions, Forecasting, Shielding
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-159529ScopusID: 2-s2.0-84873964710ISBN: 978-160560385-8OAI: oai:DiVA.org:kth-159529DiVA: diva2:785473
36th International Congress and Exhibition on Noise Control Engineering, INTER-NOISE 2007, Istanbul, Turkey, 28 August 2007 through 31 August 2007,
QC 201502032015-02-032015-02-032016-08-22Bibliographically approved