Flyover noise measurements on landing aircraft with a microphone array

Michel, U.; Barsikow, B.; Helbig, J J.; Hellmig, J M.; Schiittpelz, M.

doi:10.2514/6.1998-2336

Cited by 65 publications

(39 citation statements)

References 4 publications

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“…Acoustic measurements from flight tests [1][2][3][4][5][6] and model-scale experiments 7,8 have identified the undercarriage system and the high-lift devices, such as slats and flaps, as prominent airframe noise sources. The environmental noise impact of the civil transport fleet during landing and take-off operations must be reduced to meet increasingly stringent community noise regulations.…”

Section: Introductionmentioning

confidence: 99%

Aeroacoustic Study of a High-Fidelity Aircraft Model: Part 1-Steady Aerodynamic Measurements

Khorrami

Hannon

Neuhart

et al. 2012

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

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Section: Introductionmentioning

confidence: 99%

Aeroacoustic Study of a High-Fidelity Aircraft Model: Part 1-Steady Aerodynamic Measurements

Khorrami

Hannon

Neuhart

et al. 2012

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

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“…In the mid 1990's, the use of arrays expanded. Using a ground array in a field study, flyover noise measurements of airframe noise have been made on landing aircraft in spite of the presence of engine noise 15 . For windtunnels, sophisticated array acquisition and processing systems were built for Boeing and NASA for closed 16 and open 17 tunnel facilities.…”

Section: Introductionmentioning

confidence: 99%

Effect of directional array size on the measurement of airframe noise components

Thomas

Humphreys

1999

5th AIAA/CEAS Aeroacoustics Conference and Exhibit

128

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A study was conducted to examine the effects of overall size of directional (or phased) arrays on the measurement of aeroacoustic components. An airframe model was mounted in the potential core of an open-jet windtunnel, with the directional arrays located outside the flow in an anechoic environment. Two array systems were used; one with a solid measurement angle that encompasses 31.6° of source directivity and a smaller one that encompasses 7.2°. The arrays, and sub-arrays of various sizes, measured noise from a calibrator source and flap edge model setups. In these cases, noise was emitted from relatively small, but finite size source regions, with intense levels compared to other sources. Although the larger arrays revealed much more source region detail, the measured source levels were substantially reduced due to finer resolution compared to that of the smaller arrays. To better understand the measurements quantitatively, an analytical model was used to define the basic relationships between array to source region sizes and measured output level. Also, the effect of noise scattering by shear layer turbulence was examined using the present data and those of previous studies. Taken together, the two effects were sufficient to explain spectral level differences between arrays of different sizes. An important result of this study is that total (integrated) noise source levels are retrievable and the levels are independent of the array size as long as certain experimental and processing criteria are met. The criteria for both open and closed tunnels are discussed. The success of special

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“…Beamforming techniques are increasingly being used in the aerospace industry in order to support the development of noise reduction techniques [4][5][6][7][8][9][10][11][12]. In the case of fly-over measurements, the data generally have to be pre-processed to take into account the background noise, the propagation effects (geometrical spreading and atmospheric attenuation), ground reflection, the movement of the source and the Doppler effect [13,14].…”

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confidence: 99%