Measurement of Trailing EDGE Noise Using Directional Array and Coherent Output Power Methods

Hutcheson, Florence V.; Brooks, Thomas F.

doi:10.1260/147547202765275952

Cited by 35 publications

(55 citation statements)

References 19 publications

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“…For the airfoil case, a difference in level of about 1.5 dB remains at 12.5 kHz. As it was explained in the previous paper [10], at (and above) 12.5 kHz, the noise levels measured at the TE are affected by the presence…”

Section: Per-foot Presentationmentioning

confidence: 58%

“…The model is supported above the 2 by 3 foot rectangular nozzle by two sideplates. Treatments were applied to the trailing edge of the airfoil to modify the thickness and to model blunt trailing edges, with either square or rounded corners [10]. As depicted in Fig.…”

Section: Test Set Upmentioning

confidence: 99%

“…Grit, vortex generators or strips of serrated tape were used in certain configurations to trip the boundary layer (shown in Ref. 10). These leading edge treatments covered the first 5 % chord region on the pressure and suction side of the model.…”

Section: Test Set Upmentioning

confidence: 99%

“…In order to more clearly present the TE noise and rod noise measurements, the spectra were adjusted to represent noise generated on a per foot basis [10,14] (i.e., the noise spectra represents that generated by a model of 1 foot span for an observer located five feet away). This was achieved by applying a frequency dependent weighting function to the noise level measured by the array when focused at the center of the line source.…”

Section: Per-foot Presentationmentioning

confidence: 99%

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Effects of Angle of Attack and Velocity on Trailing Edge Noise

Hutcheson

Brooks

2004

42nd AIAA Aerospace Sciences Meeting and Exhibit

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Trailing edge (TE) noise measurements for a NACA 63-215 airfoil model are presented, providing benchmark experimental data for a cambered airfoil. The effects of flow Mach number and angle of attack of the airfoil model with different TE bluntnesses are shown. Far-field noise spectra and directivity are obtained using a directional microphone array. Standard and diagonal removal beamforming techniques are evaluated employing tailored weighting functions for quantitatively accounting for the distributed line character of TE noise. Diagonal removal processing is used for the primary database as it successfully removes noise contaminates. Some TE noise predictions are reported to help interpret the data, with respect to flow speed, angle of attack, and TE bluntness on spectral shape and peak levels. Important findings include the validation of a TE noise directivity function for different airfoil angles of attack and the demonstration of the importance of the directivity function's convective amplification terms.

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Section: Per-foot Presentationmentioning

confidence: 58%

Section: Test Set Upmentioning

confidence: 99%

Section: Test Set Upmentioning

confidence: 99%

Section: Per-foot Presentationmentioning

confidence: 99%

See 2 more Smart Citations

Effects of Angle of Attack and Velocity on Trailing Edge Noise

Hutcheson

Brooks

2004

42nd AIAA Aerospace Sciences Meeting and Exhibit

View full text Add to dashboard Cite

show abstract

“…The facility has been used in measurements of airfoil self-noise 11 , distributed trailing edge noise 12 , flap side edge noise 13 , and leading edge slat noise 14 . The 9.1 m by 6.1 m by 7.6 m anechoic test chamber has a vertically flowing 0.6 m by 0.9 m free jet exhausting through the ceiling.…”

Section: Design Of Experiments and Acoustic Testingmentioning

confidence: 99%

Aeroacoustics of Drag-Generating Swirling Exhaust Flows

Shah¹,

Mobed²,

Spakovszky³

et al. 2010

AIAA Journal

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Aircraft on approach in high-drag and high-lift configuration create unsteady flow structures which inherently generate noise. For devices such as flaps, spoilers and the undercarriage there is a strong correlation between overall noise and drag such that, in the quest for quieter aircraft, one challenge is to generate drag at low noise levels. This paper presents a rigorous aero-acoustic assessment of a novel drag concept. The idea is that a swirling exhaust flow can yield a steady, and thus relatively quiet, streamwise vortex which is supported by a radial pressure gradient responsible for pressure drag.

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Validations and improvements of airfoil trailing‐edge noise prediction models using detailed experimental data

et al. 2011

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This paper describes an extensive assessment and a step by step validation of different turbulent boundary‐layer trailing‐edge noise prediction schemes developed within the European Union funded wind energy project UpWind. To validate prediction models, measurements of turbulent boundary‐layer properties such as two‐point turbulent velocity correlations, the spectra of the associated wall pressure fluctuations and the emitted trailing‐edge far‐field noise were performed in the laminar wind tunnel of the Institute of Aerodynamics and Gas Dynamics, University of Stuttgart. The measurements were carried out for a NACA 643‐418 airfoil, at Re = 2.5 ×106, angle of attack of −6° to 6°. Numerical results of different prediction schemes are extensively validated and discussed elaborately. The investigations on the TNO‐Blake noise prediction model show that the numerical wall pressure fluctuation and far‐field radiated noise models capture well the measured peak amplitude level as well as the peak position if the turbulence noise source parameters are estimated properly including turbulence anisotropy effects. Large eddy simulation based computational aeroacoustic computations show good agreements with measurements in the frequency region higher than 1 kHz, whereas they over‐predict the sound pressure level in the low‐frequency region. Copyright © 2011 John Wiley & Sons, Ltd.

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Measurement of Trailing EDGE Noise Using Directional Array and Coherent Output Power Methods

Cited by 35 publications

References 19 publications

Effects of Angle of Attack and Velocity on Trailing Edge Noise

Effects of Angle of Attack and Velocity on Trailing Edge Noise

Aeroacoustics of Drag-Generating Swirling Exhaust Flows

Validations and improvements of airfoil trailing‐edge noise prediction models using detailed experimental data

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