Broadband characterisation of in-duct acoustic sources using an equivalent source approach

Meggitt, JWR; Elliott, AS; Moorhouse, AT; Banwell, G; Hopper, H; Lamb, J

Abstract

This paper is concerned with the development of an experimental method capable of independently characterising low Mach number, in-duct fluid machines, such as pumps, fans, etc. The aim is to propose and test a source characterisation method that is suitable for acoustic simulation and the construction Virtual Acoustic Prototypes. Such a requirement demands that the source characterisation be (a) independent, so that components can be virtually (re)combined within different assemblies and (b) valid over a wide frequency range so as to enable the output of a virtual assembly to be auralised. In this regard, standard methods based on sound power are not suitable. An equivalent source approach is proposed, based on a two-stage measurement procedure in which source strengths are obtained by solving an inverse problem. The experimental application of the procedure is illustrated as part of a case study where a high speed compressor unit is independently characterised and the resulting source data used to predict the operational response in a new assembly. Three frequency ranges are identified based on plane wave, modal and statistical behavior within the duct. The same measured data is used within each regime but subject to different processing according to different assumptions. Predictions are shown to be in good agreement with the directly measured response over a broad frequency range (100 Hz–10 kHz).

Citation

Meggitt, J., Elliott, A., Moorhouse, A., Banwell, G., Hopper, H., & Lamb, J. (2019). Broadband characterisation of in-duct acoustic sources using an equivalent source approach. Journal of Sound and Vibration, 442(Mar 19), 800-816. https://doi.org/10.1016/j.jsv.2018.10.041

• Journal Article Type: Article
• Acceptance Date: Oct 22, 2018
• Online Publication Date: Nov 21, 2018
• Publication Date: Mar 3, 2019
• Deposit Date: Feb 8, 2019
• Publicly Available Date: Nov 21, 2019
• Journal: Journal of Sound and Vibration
• Print ISSN: 0022-460X
• Publisher: Elsevier
• Volume: 442
• Issue: Mar 19
• Pages: 800-816
• DOI: https://doi.org/10.1016/j.jsv.2018.10.041
• Publisher URL: https://doi.org/10.1016/j.jsv.2018.10.041
• Related Public URLs: https://www.journals.elsevier.com/journal-of-sound-and-vibration
• Additional Information: Projects : HVAP