Fan Noise Prediction with Applications to Aircraft System Noise Assessment

Nark, Douglas M.; Envia, Edmane; Burley, Casey L.

doi:10.2514/6.2009-3291

Cited by 11 publications

(10 citation statements)

References 12 publications

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“…8,9,26 The current study addressed source specification issues for the case of rotor-stator interaction to illustrate changes in 2xBPF predictions when additional source content was included. Following previous statistical studies, 27 the influence of relative phase between source modes was also shown through numerical experimentation.…”

Section: Discussionmentioning

confidence: 99%

“…For situations in which the source pressure is available, this greatly simplifies the conversion to the required acoustic potential. Previously, 9 this information was obtained by using the LINFLUX 8,24 code to compute the rotor-stator interaction tones generated as a result of the mean perturbations in the fan rotor wake impinging on the stator. In this study, the acoustic potential source profiles were computed using various combinations of the measured source modes obtained from the aforementioned rotating rake.…”

Section: B Implementationmentioning

confidence: 99%

“…Following the paradigm of the previous assessments, a subsequent study 9 investigated a well known empirical method, NASA's Aircraft Noise Prediction Program (ANOPP), 1 and a newly developed coupled computational approach via comparison with measured sideline acoustic measurements from a benchmark fan noise test. The specific fan configuration, the Advanced Ducted Propulsor (ADP) Fan 1, 10,11 was chosen because it exhibited strong RSI tones.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On Acoustic Source Specification for Rotor-Stator Interaction Noise Prediction

Nark

Envia

Burley

2010

16th AIAA/CEAS Aeroacoustics Conference

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This paper describes the use of measured source data to assess the effects of acoustic source specification on rotor-stator interaction noise predictions. Specifically, the acoustic propagation and radiation portions of a recently developed coupled computational approach are used to predict tonal rotor-stator interaction noise from a benchmark configuration. In addition to the use of full measured data, randomization of source mode relative phases is also considered for specification of the acoustic source within the computational approach. Comparisons with sideline noise measurements are performed to investigate the effects of various source descriptions on both inlet and exhaust predictions. The inclusion of additional modal source content is shown to have a much greater influence on the inlet results. Reasonable agreement between predicted and measured levels is achieved for the inlet, as well as the exhaust when shear layer effects are taken into account. For the number of trials considered, phase randomized predictions follow statistical distributions similar to those found in previous statistical source investigations. The shape of the predicted directivity pattern relative to measurements also improved with phase randomization, having predicted levels generally within one standard deviation of the measured levels.

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Section: Discussionmentioning

confidence: 99%

Section: B Implementationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On Acoustic Source Specification for Rotor-Stator Interaction Noise Prediction

Nark

Envia

Burley

2010

16th AIAA/CEAS Aeroacoustics Conference

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“…Ferrecchia et al (2003) utilized numerical simulation to capture the development process of rotor wakes. The noise source was separated into several components through numerical methods by Nark et al (2009) and Peters and Spakovszky (2012), and noise prediction was carried out. Cooper and Peake (2006) used the wake evolution and the quasi-3D strip method to develop an asymptotic technique and a new model for the wake interaction.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Unsteady Flows and Noise in Rotor-Stator Interaction with Adjustable Lean Vane

Liu¹,

Ouyang²,

Wu³

et al. 2014

Engineering Applications of Computational Fluid Mechanics

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ABSTRACT:The paper is a study of the noise reduction effects of the stator lean angle. Firstly, a numerical study has been carried out to investigate the unsteady characteristics of the flow induced by the rotor-stator interaction. To obtain the rotor"s wake, the distribution of the RMS pressure and the pressure disturbance coefficient, the compressor with an adjustable stator lean angle has been numerically studied. Then the compressor was experimentally tested at 11 different lean angles to obtain the free field noise spectra. Both the unsteady flow property and noise characteristics are discussed on the basis of the Computational Fluid Dynamics (CFD) results. The results indicate that (1) the pressure fluctuation of stator is the main source of the interaction noise; (2) the phase of rotor"s wake can be tuned by the lean angle of the stator; (3) the distribution of the first harmonic of tone noise decides the distribution of total Sound Pressure level (SPL); and (4) stator with positive lean angle has better noise reduction than negative one and the lean angle should exceed 10° for better noise reduction.

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“…The fan stage has 22 blades and 54 stator vanes in its baseline configuration. This configuration was chosen because of its use in previous studies 8,9,10 and the availability of measured acoustic data 6,7 for further model validation. The cross-section of the SDT test configuration is shown in Figure 2 with candidate inlet and aft acoustic liner locations shaded in green.…”

Section: Test Configurationmentioning

confidence: 99%

Broadband Liner Optimization for the Source Diagnostic Test Fan

Nark

Jones

2012

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

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The broadband component of fan noise has grown in relevance with the utilization of increased bypass ratio and advanced fan designs. Thus, while the attenuation of fan tones remains paramount, the ability to simultaneously reduce broadband fan noise levels has become more appealing. This paper describes a broadband acoustic liner optimization study for the scale model Source Diagnostic Test fan. Specifically, in-duct attenuation predictions with a statistical fan source model are used to obtain optimum impedance spectra over a number of flow conditions for three liner locations in the bypass duct. The predicted optimum impedance information is then used with acoustic liner modeling tools to design liners aimed at producing impedance spectra that most closely match the predicted optimum values. Design selection is based on an acceptance criterion that provides the ability to apply increased weighting to specific frequencies and/or operating conditions. Typical tonal liner designs targeting single frequencies at one operating condition are first produced to provide baseline performance information. These are followed by multiple broadband design approaches culminating in a broadband liner targeting the full range of frequencies and operating conditions. The broadband liner is found to satisfy the optimum impedance objectives much better than the tonal liner designs. In addition, the broadband liner is found to provide better attenuation than the tonal designs over the full range of frequencies and operating conditions considered. Thus, the current study successfully establishes a process for the initial design and evaluation of novel broadband liner concepts for complex engine configurations.

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Fan Noise Prediction with Applications to Aircraft System Noise Assessment

Cited by 11 publications

References 12 publications

On Acoustic Source Specification for Rotor-Stator Interaction Noise Prediction

On Acoustic Source Specification for Rotor-Stator Interaction Noise Prediction

Investigation of Unsteady Flows and Noise in Rotor-Stator Interaction with Adjustable Lean Vane

Broadband Liner Optimization for the Source Diagnostic Test Fan

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