“Buzz-saw” noise: A comparison of measurement with prediction
✍ Scribed by A. McAlpine; M.J. Fisher; B.J. Tester
- Book ID
- 104031983
- Publisher
- Elsevier Science
- Year
- 2006
- Tongue
- English
- Weight
- 525 KB
- Volume
- 290
- Category
- Article
- ISSN
- 0022-460X
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✦ Synopsis
Accurate prediction of ''buzz-saw'' noise in a turbofan inlet duct necessitates consideration of nonlinear acoustics, modelling a complete fan blade set, modelling an acoustic liner, and calculations at high frequencies. A recent series of papers has described new work concerning the application of onedimensional propagation models to the prediction of buzz-saw noise. A numerical model, termed the frequency domain numerical solution or FDNS, has been developed. It can be used to calculate the nonlinear propagation of the rotor-alone pressure field in either a rigid or acoustically-lined inlet duct. From this the in-duct noise level of the buzz-saw tones can be determined. In previous work, validation of this method by comparison with in-duct noise measurements has been limited to rigid inlet ducts, because of the lack of availability of suitable measurements from lined ducts. In this article new measurements of buzz-saw noise in an acoustically-lined inlet duct are utilized. A comparison of measurements of buzz-saw noise in a lined inlet duct, and noise predictions from numerical simulations by the FDNS is presented. The detailed measurements reveal the effect of an acoustic liner on buzz-saw noise. The suitability of the numerical model to be used to provide realistic noise predictions for supersonic ducted fans is also examined.
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