Advanced Computational and Experimental Techniques for Nacelle Liner Performance Evaluation

Gerhold, Carl H.; Jones, Michael G.; Brown, Martha C.; Nark, Douglas M.

doi:10.2514/6.2009-3168

Cited by 7 publications

(4 citation statements)

References 6 publications

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“…The results obtained in the present study are comparable to those obtained in the previous study 15 . When the liner treatment is symmetric, the difference between the 0-offset and 1D-offset attenuation is small.…”

Section: Left Rightsupporting

confidence: 83%

“…Figure 16 shows the CDTR with the flow path in the 1D-offset curvature. The offset curvature was investigated in a previous paper by the authors 15 with the duct in the 'exhaust' orientation only. It was found that when the treatment is symmetric, the attenuation with 1D-offset is approximately 2 dB greater than the straight duct at all frequencies except at the peak, where the two results are equal.…”

Section: Flow Path Curvature Effectmentioning

confidence: 99%

“…For the asymmetric case in the previous paper 15 , only the 1D offset was analyzed but with liner treatment on the left wall compared to treatment on the right wall. Liner treatment on the left wall produced higher attenuation than with the treatment on the right wall, although the difference decreased with increasing vertical mode order.…”

Section: Left Rightmentioning

confidence: 99%

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Configuration Effects on Liner Performance

Gerhold

Brown

Jones

et al. 2012

18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference)

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The acoustic performance of a duct liner depends not only on the intrinsic properties of the liner but also on the configuration of the duct in which it is used. A series of experiments is performed in the NASA Langley Research Center Curved Duct Test Rig (at Mach 0.275) to evaluate the effect of duct configuration on the acoustic performance of single degree of freedom perforate-over-honeycomb liners. The liners form the sidewalls of the duct's test section. Variations of duct configuration include: asymmetric (liner on one side and hard wall opposite) and symmetric (liner on both sides) wall treatment; inlet and exhaust orientation, in which the sound propagates either against or with the flow; and straight and curved flow path. The effect that duct configuration has on the overall acoustic performance, particularly the shift in frequency and magnitude of peak attenuation, is quantified. The redistribution of incident mode content is shown. The liners constitute the side walls of the liner test section and the scatter of incident horizontal order 1 mode by the asymmetric treatment and order 2 mode by the symmetric treatment into order 0 mode is shown. Scatter of order 0 incident modes into higher order modes is also shown. This redistribution of mode content is significant because it indicates that the liner design can be manipulated such that energy is scattered into more highly attenuated modes, thus enhancing liner performance.

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Section: Left Rightsupporting

confidence: 83%

Section: Flow Path Curvature Effectmentioning

confidence: 99%

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Configuration Effects on Liner Performance

Gerhold

Brown

Jones

et al. 2012

18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference)

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“…Initial numerical studies and lower TRL tests were used to define the implementation and validate various tools. 7,10,15,18 As confidence in the overall methodology increased, design and testing efforts were pursued in the NASA Glenn Advanced Noise Control Fan (ANCF) Rig, 19–21 9- by 15-Foot Low Speed Wind Tunnel, 22,23 and Aeroacoustic Propulsion Laboratory (AAPL). 24 Lessons learned from these projects culminated in the design and flight testing of an advanced inlet liner on the Quiet Technology Demonstrator 3 (QTD3).…”

Section: Application and Assessment Of The Liner Design Methodologymentioning

confidence: 99%

An acoustic liner design methodology based on a statistical source model

Nark

Jones

2021

International Journal of Aeroacoustics

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The attenuation of fan tones remains an important aspect of fan noise reduction for high bypass ratio turbofan engines. However, as fan design considerations have evolved, the simultaneous reduction of broadband fan noise levels has gained interest. Advanced manufacturing techniques have also opened new possibilities for the practical implementation of broadband liner concepts. To effectively address these elements, practical acoustic liner design methodologies must provide the capability to efficiently predict the acoustic benefits of novel liner configurations. This paper describes such a methodology to design and evaluate multiple candidate liner configurations using realistic, three dimensional geometries for which minimal source information is available. The development of the design methodology has been guided by a series of studies culminating in the design and flight test of a low drag, broadband inlet liner. The excellent component and system noise benefits obtained in this test demonstrate the effectiveness of the broadband liner design process. They also illustrate the value of the approach in concurrently evaluating multiple liner designs and their application to various locations within the aircraft engine nacelle. Thus, the design methodology may be utilized with increased confidence to investigate novel liner configurations in future design studies.

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