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New developments in near-field acoustic holography [PDF]
, 2007 In the field of noise-control engineering, information about the individual strength, andlocation, of the most dominant sources is of vital importance. This information allows theacoustic engineer to take effective measures in his effort to reduce the emitted acoustic noiselevels.
Roozen, N.B. +3 more
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Near field acoustic holography with microphones on a rigid sphere (L) [PDF]
The Journal of the Acoustical Society of America, 2011 Spherical near field acoustic holography (spherical NAH) is a technique that makes it possible to reconstruct the sound field inside and just outside a spherical surface on which the sound pressure is measured with an array of microphones. This is potentially very useful for source identification. The sphere can be acoustically transparent or it can be
Finn, Jacobsen +3 more
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Extension of measurement surface in near-field acoustic holography
The Journal of the Acoustical Society of America, 2004In near-field acoustic holography, when measurements are made over a limited surface, there has been recent interest in numerically enlarging the measurement surface tangentially. Current algorithms use iterative methods to extrapolate the field tangentially outward. An algorithm based on the method of superposition is applied here which may be used to
Sarkissian Angie
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A partial field decomposition algorithm and its examples for near-field acoustic holography [PDF]
Journal of the Acoustical Society of America, 2004 In this paper we introduce a practical algorithm that can accurately implement partial field decomposition for near-field acoustic holography (NAH). Unlike other methods, the algorithm does not require sensors near sources because it uses calculations ...
Yang-Hann Kim, Kim Yang-Hann
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Interior near-field acoustical holography in flight
The Journal of the Acoustical Society of America, 2000In this paper boundary element methods (BEM) are mated with near-field acoustical holography (NAH) in order to determine the normal velocity over a large area of a fuselage of a turboprop airplane from a measurement of the pressure (hologram) on a concentric surface in the interior of the aircraft.
E G, Williams +4 more
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Planar near-field acoustical holography in a moving medium
The Journal of the Acoustical Society of America, 2002Near-field acoustical holography (NAH) is a well-established method to study acoustic radiation near a stationary sound source in a homogeneous, stationary medium. However, the current theory of NAH is not applicable to moving sound sources, such as automobiles and trains.
Richard J, Ruhala, David C, Swanson
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Multisource statistically optimized near-field acoustical holography
The Journal of the Acoustical Society of America, 2015This paper presents a reduced-order approach to near-field acoustical holography (NAH) that allows the user to account for sound fields generated by multiple spatially separated sources. In this method, an equivalent wave model (EWM) of a given field is formulated to include combinations of planar, cylindrical, spherical, or other elementary wave ...
Alan T, Wall +2 more
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ACOUSTO-OPTIC SENSING FOR NEAR-FIELD ACOUSTIC HOLOGRAPHY
Inter-Noise 2022, 2023Near-field acoustic holography (NAH) is a very powerful and widely used technique for the study of complex acoustic radiators. NAH enables to quickly understand how a complex source radiates into the medium. The technique is particularly suitable at low frequencies.
SA VERBURG +2 more
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Measurement of confined acoustic sources using near-field acoustic holography
The Journal of the Acoustical Society of America, 2009Due to excessive reverberation or to the presence of secondary noise sources, characterization of sound sources in enclosed space is rather difficult to perform. In this paper a process layer is used to recover the pressure field that the studied source would have radiated in free space.
Langrenne, Christophe +2 more
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Near-field acoustical holography in an enclosed space
The Journal of the Acoustical Society of America, 1990In wind and water tunnels, the interaction of flow with rotating and nonrotating structures is a source of radiated noise. To characterize both the source and noise field radiated by sources operating in wind or water tunnels, near-field acoustical holography algorithms for the nonintrusive reconstruction of the velocity of the source and the complete ...
Charles J. Konzelman +1 more
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