Modelling of ducted noise sources in the proximity of acoustic liners

Palleja-Cabre, Sergi; Tester, Brian J.; Astley, R.J.

doi:10.1016/j.jsv.2021.116548

Cited by 10 publications

(7 citation statements)

References 32 publications

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“…The total acoustic field at any point of the domain shown in Fig. 1 can then be obtained by imposing continuity of the unsteady mass and momentum at the two interfaces, I-II and II-III, and solving the resulting matching equations as detailed in [10]. The inclusion of reflections from a duct termination is implemented in the mode-matching model by assuming that the incident and reflected modes at the duct termination are linked by a reflection coefficient matrix .…”

Section: Inclusion Of a Termination In The Mode-matching Schemementioning

confidence: 99%

“…Hence, the amplitude of the reflected mode ( , ), + , is the summation over all the contributions of the incident modes ( , ) allowing for radial scattering. The approach implemented here simply adds a set of equations to account for the new set of unknowns + previously set to zero in [10]. That is…”

Section: Inclusion Of a Termination In The Mode-matching Schemementioning

confidence: 99%

“…The model presented here includes the coupling of the fan sources to sound propagation and noise suppression. Green's functions are used for this purpose, building upon previous analytical studies [9,10]. Improvements to previous work include modelling of an inlet termination and of distributed rotating sources.…”

Section: Introductionmentioning

confidence: 99%

“…The rest of the paper is organised as follows. The analytical model for the noise sources, duct propagation and attenuation is described in Section II, with emphasis on the new additions relative to the model in [10], and analytical…”

Section: Introductionmentioning

confidence: 99%

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Modeling of Over-Tip-Rotor Liners for the Suppression of Fan Noise

2022

Self Cite

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Fan noise is one of the dominant sources of aircraft engine noise, both at approach and at take-off. Improved attenuation of fan noise with acoustic liners and the reduction of fan noise at source remain key technology challenges for civil aviation in the foreseeable future. Over-Tip-Rotor (OTR) acoustic treatments have been investigated experimentally during the last decade and significant fan noise reductions have been measured, most recently using a single rotor and multiple lined circumferential grooves. This paper describes an analytical OTR

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Section: Inclusion Of a Termination In The Mode-matching Schemementioning

confidence: 99%

Section: Inclusion Of a Termination In The Mode-matching Schemementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modeling of Over-Tip-Rotor Liners for the Suppression of Fan Noise

2022

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“…In particular, the tip clearance is a relevant source of the self-noise because the pressure difference between the two sides of a blade starts a tip-leakage vortex, which interacts with the blade tip edge [22,23]. To this end, the over-the-tip liners (OTLs) have been investigated during the past decades as a technology with the potential to attenuate the fan noise in turbofan engines [24]. This concept consists of treating the casing surrounding the fan blades by fitting an acoustic liner.…”

Section: A Reduction Of Noise At the Sourcementioning

confidence: 99%

Development of the SmartAnswer Demonstrator: a Didactic Wind Tunnel for Aeroacoustic Applications

Tamaro

Zamponi

Schram

2022

28th AIAA/CEAS Aeroacoustics 2022 Conference

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A small didactic wind tunnel demonstrator has been designed and manufactured at the von Karman Institute for Fluid Dynamics to illustrate the physical principles at stake in flow-induced noise generation, offer an audible perception of the effectiveness of noise-mitigation strategies, and serve as a practical test bench for aeroacoustic education and research. Seven mitigation technologies are embedded in a single facility, which addresses the noise generation by an airfoil, noise propagation in a duct, and noise transmission through a flexible panel. A challenging objective of this facility was to offer a perceptible impression of various aeroacoustic noise mechanisms at low flow speeds and a live assessment of the effectiveness of the noisereduction technologies. Different approaches combining multiple microphones, advanced signal-processing techniques, and real-time audio feedback have been implemented to this end. The results establish that the demonstrator enables a clear perception of the effectiveness of the noise-mitigation technologies. The facility is also suitable for fast and inexpensive preliminary investigations of future noise-reduction concepts, taking advantage of rapid prototyping techniques.

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Marine propulsor underwater radiated noise emission characterization using sensor arrays

Tanttari,

Hynninen

2024

Applied Acoustics

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Modelling of ducted noise sources in the proximity of acoustic liners

Cited by 10 publications

References 32 publications

Modeling of Over-Tip-Rotor Liners for the Suppression of Fan Noise

Modeling of Over-Tip-Rotor Liners for the Suppression of Fan Noise

Development of the SmartAnswer Demonstrator: a Didactic Wind Tunnel for Aeroacoustic Applications

Marine propulsor underwater radiated noise emission characterization using sensor arrays

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