Source Characterization By Correlation Techniques

Blake, William K.; Lynch, Denis A.

doi:10.1007/978-3-662-05058-3_4

Cited by 8 publications

(5 citation statements)

References 6 publications

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“…Trailing edge noise measurements however show that a correlation-filtering technique is required, as anticipated 38 . An additional silencer is not considered to be necessary, since most of the additional sound stems from the nozzle.…”

Section: Discussionmentioning

confidence: 89%

Concept, design and characterization of a small aeroacoustic wind tunnel facility with application to airfoil measurements

Winkler¹,

Carolus²

2009

Noise Control Eng. J.

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Experimental investigation of flow-induced sound and sources of soundnecessitates an adequate environment of low interfering noise and suppression of unwanted sources of sound. In order to investigate the sound from fluidstructure interactions, a low-noise wind tunnel has been designed and implemented. This paper gives an overview of the design criteria and specifications, along with an aeroacoustic and aerodynamic characterization of the facility. The suitability to airfoil self-noise studies is explored and first measurements with a model airfoil are presented. The paper concludes with an outlook on future applications. © 2009 Institute of Noise Control Engineering.

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Section: Discussionmentioning

confidence: 89%

Concept, design and characterization of a small aeroacoustic wind tunnel facility with application to airfoil measurements

Winkler¹,

Carolus²

2009

Noise Control Eng. J.

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“…To isolate the airfoil self noise from ambient sound sources, we take advantage of the fact that the overall airfoil self noise is dominated by the noise emissions occurring at the TE. The dipole characteristic of TEN offers the application of a filtering technique derived by Blake and Lynch [22]. The signals of the two TE phased-matched microphones (M1 and M2 in figure 2, left) should be equal in magnitude but 180° out of phase.…”

Section: Acoustic Signal Processing Techniquesmentioning

confidence: 99%

Reduction of airfoil trailing edge noise by trailing edge blowing

Gerhard¹,

Erbslöh²,

Carolus³

2014

J. Phys.: Conf. Ser.

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“…For example, in [Blake 2002;p.233] the sound produced at the trailing edge of an airfoil is described as "[...] radiated by a line of sources along the edge, with equal magnitudes to both sides of the airfoil, and the sound radiated to one side is 180 degrees out of phase with the sound radiated to the other," that is, a line of dipoles located along the trailing edge, with the out-of-phase lobes perpendicular to the airfoil.…”

Section: Christian Bouchard Phd Thesismentioning

confidence: 99%

Beamforming with microphone arrays for directional sources

Bouchard

Havelock

Bouchard

2009

The Journal of the Acoustical Society of America

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Beamforming is done with an array of sensors to achieve a directional or spatially-specific response by using a model of the arriving wavefront. Real acoustic sources may deviate from the conventional plane wave or monopole model, causing decreased array gain or a total breakdown of beamforming. An alternative to beamforming with the conventional source model is presented which avoids this by using a more general source model. The proposed method defines a set of “sub-beamformers,” each designed to respond to a different spatial mode of the source. The outputs of the individual sub-beamformers are combined in a weighted sum to give an overall output of better quality than that of a conventional (monopole) beamformer. It is shown that with appropriate weighting, the optimum array gain can be achieved. A simple method is demonstrated to estimate the weighted sum, based on the observed data. The variance and bias of the estimate in the presence of noise are evaluated. Simulation and experimentally measured results are shown for a simple directive source. In the experiment, the proposed method provides an array gain of about 11 dB while beamforming using a point source model achieves only −4 dB.

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Source Characterization By Correlation Techniques

Cited by 8 publications

References 6 publications

Concept, design and characterization of a small aeroacoustic wind tunnel facility with application to airfoil measurements

Concept, design and characterization of a small aeroacoustic wind tunnel facility with application to airfoil measurements

Reduction of airfoil trailing edge noise by trailing edge blowing

Beamforming with microphone arrays for directional sources

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