Auralization of Flyover Noise from Open Rotor Engines Using Model Scale Test Data

Rizzi, Stephen A.; Stephens, David B.; Berton, Jeffrey J.; Zante, Dale E. Van; Wojno, John; Goerig, Trevor

doi:10.2514/6.2014-2750

Cited by 6 publications

(6 citation statements)

References 14 publications

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“…The data processing steps required for scaling and flight effects largely follow the methods previously developed for system noise prediction of HWB aircraft 20,21 and auralization of open rotor engines. 7 That method was itself adopted from the process developed by Guynn et al 22 for converting scale model wind tunnel acoustic data to full scale flight condition data. The process is summarized below.…”

Section: System Noise Assessmentsmentioning

confidence: 99%

“…As the new concepts are yet to be built, it is not possible to test human response using measured flyover noise. Fortunately, auralization has been shown to be an effective means of simulating aircraft flyover noise using semi-empirical models, 5 computational aeroacoustic analyses, 6 and wind tunnel 7 and flight 8 test data to characterize the source. The auralization process itself involves: source noise synthesis, using one or more of the above, in a frame with the moving source; and propagation of the resulting pressure time history through application of a time-varying: gain to simulate spherical spreading; time delay to Doppler shift; and filter to simulate atmospheric absorption and ground plane impedance.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Auralization of NASA N+2 Aircraft Concepts from System Noise Predictions

Rizzi

Burley

Thomas

2016

22nd AIAA/CEAS Aeroacoustics Conference

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Auralization of aircraft flyover noise provides an auditory experience that complements integrated metrics obtained from system noise predictions. Recent efforts have focused on auralization methods development, specifically the process by which source noise information obtained from semi-empirical models, computational aeroacoustic analyses, and wind tunnel and flight test data, are used for simulated flyover noise at a receiver on the ground. The primary focus of this work, however, is to develop full vehicle auralizations in order to explore the distinguishing features of NASA's N+2 aircraft vis-à-vis current fleet reference vehicles for single-aisle and large twin-aisle classes. Some features can be seen in metric time histories associated with aircraft noise certification, e.g., tone-corrected perceived noise level used in the calculation of effective perceived noise level. Other features can be observed in sound quality metrics, e.g., loudness, sharpness, roughness, fluctuation strength and tone-to-noise ratio. A psychoacoustic annoyance model is employed to establish the relationship between sound quality metrics and noise certification metrics. Finally, the auralizations will serve as the basis for a separate psychoacoustic study aimed at assessing how well aircraft noise certification metrics predict human annoyance for these advanced vehicle concepts.

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Section: System Noise Assessmentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Auralization of NASA N+2 Aircraft Concepts from System Noise Predictions

Rizzi

Burley

Thomas

2016

22nd AIAA/CEAS Aeroacoustics Conference

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“…These differences were not captured by the A-weighted metrics and the results highlighted the need to express differences in aircraft sounds in an improved, objective manner. Another study, focused on the auralized sounds of future Counter Rotating Open Rotor (CROR) engines by Rizzi et al [8], has also shown that audible changes in the quality of the sounds due to improved blade designs are not always clearly expressed in terms of EPNL values. By starting with a focus on comparison of synthetic and measured aircraft sounds, various factors can be investigated which play an important role in distinguishing between aircraft sound signatures in general.…”

Section: Introductionmentioning

confidence: 99%

Objective quantification of perceived differences between measured and synthesized aircraft sounds

Sahai

Snellen

Simons

2018

Aerospace Science and Technology

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This paper presents an approach with which perceived audible differences in aircraft sounds can be quantified and presented in an objective manner. The objective quantification of the subjectively heard audible differences is intended to serve two primary goals. It can firstly enable developers of auralization technology to make the auralized sounds more realistic by identifying in which aspects the synthesized sounds differ from their real-life counterparts and to what extent. The quantification can secondly provide an improved and more detailed means of distinguishing between aircraft sounds in general, beyond the conventional metrics of A-weighted Sound Pressure level (dBA) or Effective Perceived Noise Level (EPNL) used currently to assess aircraft noise. In this study sound quality metrics are used to quantify the differences in aircraft sounds. These metrics are widely used in other industries such as the automotive sector. Audio files of a reference aircraft, made over identical flight paths at a noise monitoring station in the vicinity of Schiphol airport, are compared in terms of both conventional and sound quality metrics for four measured and four auralized audio files. It is observed from the comparison that differences that may appear small in the conventional metrics can be significant in terms of the sound quality metrics. Significant differences in measured and synthesized sounds are observed for the aircraft considered in this study with regards to the tonal content and fluctuations in amplitude that occur over time. The conventional metrics are seen to capture the overall loudness aspect of aircraft sounds, but give no clear information regarding which spectral or temporal characteristics cause the sounds to be perceived as audibly different.

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“…NASA has been actively using aircraft noise auralizations of fan tonal and jet broadband noise to better understand their subjective perceptions and has attempted to make the synthetic auralizations sound more realistic via incorporation of temporal fluctuations [10,11]. NASA has also auralized synthetic audio of future Hybrid Wing Body and CROR aircraft flyovers for demonstration of their noise reduction and acceptance possibilities [12,13]. The National Aerospace Laboratory (NLR) of the Netherlands further developed the HMD visualization capability -the Virtual Community Noise Simulator (VCNS) and performed auralizations of propagated noise spectra on the ground [14].…”

Section: Introductionmentioning

confidence: 99%