Results 291 to 300 of about 5,629,785 (335)
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The Journal of the Acoustical Society of America, 1955
Extensions of earlier studies [J. Acoust. Soc. Am. 26, No. 2(1953)] on ventilation system noise are reported. It is shown here that in properly engineered ventilation systems the over-all sound power level in decibels re 1013a watt is related to the horsepower rating of the fan motor by the formula: PWL = 100+10 1og10hp.
Leo L. Beranek +2 more
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Extensions of earlier studies [J. Acoust. Soc. Am. 26, No. 2(1953)] on ventilation system noise are reported. It is shown here that in properly engineered ventilation systems the over-all sound power level in decibels re 1013a watt is related to the horsepower rating of the fan motor by the formula: PWL = 100+10 1og10hp.
Leo L. Beranek +2 more
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Journal of Vibration and Acoustics, 1991
This paper presents a method for assessing the extent of casing noise radiation of a centrifugal fan relative to the aeroacoustic sources associated with the inlet box of the fan. Central to the method is a boundary element program which is used to compute the acoustic pressures on the surfaces of the fan casing in terms of its surface vibration which ...
G. H. Koopmann, W. Neise, K. A. Cunefare
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This paper presents a method for assessing the extent of casing noise radiation of a centrifugal fan relative to the aeroacoustic sources associated with the inlet box of the fan. Central to the method is a boundary element program which is used to compute the acoustic pressures on the surfaces of the fan casing in terms of its surface vibration which ...
G. H. Koopmann, W. Neise, K. A. Cunefare
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The Journal of the Acoustical Society of America, 1981
A fan for moving a gaseous fluid, e.g., air, is described in which the high audible frequency noise resulting from the phenomenon occurring at the trailing edges of the blades, known as vortex shedding, is reduced. This is accomplished by notching an edge of each of the blades so that the pattern of vortices leaving the blade, which causes the noise ...
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A fan for moving a gaseous fluid, e.g., air, is described in which the high audible frequency noise resulting from the phenomenon occurring at the trailing edges of the blades, known as vortex shedding, is reduced. This is accomplished by notching an edge of each of the blades so that the pattern of vortices leaving the blade, which causes the noise ...
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Passive Noise Reduction for a Contra-Rotating Fan
Volume 1A: Aircraft Engine; Fans and Blowers, 2014There has been renewed interest in the contra-rotating (CR) fan configuration in aviation and other applications where size and weight are important design factors. Contra-rotation recovers swirl energy compared with the single-rotor design, but this advantage is not fully harnessed due to, perhaps, the issue of noise. This study explores passive noise
Wang, C, Huang, L
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The Journal of the Acoustical Society of America, 1956
Early studies [J. Acoust. Soc. Am. 25, 313 (1953); J. Acoust. Soc. Am. 25, 322 (1953)] related noise output to fan horsepower and indicated the usefulness of this relation in predicting noise in ventilating systems. More comprehensive measurements yielded a simpler, more accurate equation relating noise and rated horsepower for large centrifugal fans ...
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Early studies [J. Acoust. Soc. Am. 25, 313 (1953); J. Acoust. Soc. Am. 25, 322 (1953)] related noise output to fan horsepower and indicated the usefulness of this relation in predicting noise in ventilating systems. More comprehensive measurements yielded a simpler, more accurate equation relating noise and rated horsepower for large centrifugal fans ...
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Journal of Thermal Science, 2008
In the wake-rotor interaction fan noise, a number of the interacting modes at the blade passing frequency (BPF) and its harmonics are generated which are prescribed by the number of stator and rotor blades etc. In the present study, the dominant mode is tried to be suppressed by the secondary sound from the loudspeaker actuators.
Nobuhiko Yamasaki, Hirotoshi Tajima
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In the wake-rotor interaction fan noise, a number of the interacting modes at the blade passing frequency (BPF) and its harmonics are generated which are prescribed by the number of stator and rotor blades etc. In the present study, the dominant mode is tried to be suppressed by the secondary sound from the loudspeaker actuators.
Nobuhiko Yamasaki, Hirotoshi Tajima
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10th AIAA/CEAS Aeroacoustics Conference, 2004
This paper concerns the sound generated at the leading edge of a turbofan blade in an aeroengine when the blade is struck by a convected gust. The gust is localised in space, e.g., in a narrow wake, and is localised in time, producing a highly unsteady impulsive sound field. The relative motion between the blade and the flow is subsonic.
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This paper concerns the sound generated at the leading edge of a turbofan blade in an aeroengine when the blade is struck by a convected gust. The gust is localised in space, e.g., in a narrow wake, and is localised in time, producing a highly unsteady impulsive sound field. The relative motion between the blade and the flow is subsonic.
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Noise Notes, 2000
The cause of high noise generated by a table fan has been investigated. The noise source was identified by sound intensity mapping and frequency analysis of noise signal. The base of the fan stand was radiating high noise. The cause of this noise was found to be due to the resonance of fan stand.
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The cause of high noise generated by a table fan has been investigated. The noise source was identified by sound intensity mapping and frequency analysis of noise signal. The base of the fan stand was radiating high noise. The cause of this noise was found to be due to the resonance of fan stand.
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Effect of porous casing on small axial-flow fan noise
, 2021Naitong Liu +3 more
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Acoustic noise control for fans
The Journal of the Acoustical Society of America, 1989Apparatus for the abatement of noise from cooling fans primarily in computer and business equipment. Noise of mechanical origin is reduced by damping the fan casing, by mass-loading the casing (at low frequencies), by isolating the casing from its surrounds, and by absorbing some of the noise as it is radiated from the fan casing.
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