Results 211 to 220 of about 35,280 (262)

NOISE OF VENTILATING FANS

Journal of the American Society for Naval Engineers, 1953
Using the apparatus described by Reynolds, Wilson, and Beranek, measurements were made of the acoustic power in watts in twenty-four bands each one-third octave wide for three vaneaxial-type and two centrifugal-type fans of grades sizes. Formulas were derived empirically, enabling the computation of the over-all acoustic power of the noise for the ...
C. E. Peistrup, J. E. Wesler
  +4 more sources

Noise control of a table fan

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.
openaire   +1 more source

Noise of Centrifugal Fans

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
openaire   +1 more source

Subsonic fan noise

Journal of Sound and Vibration, 1971
Abstract Helicopter rotor noise theories are used to determine the noise of subsonic fans produced solely by the rotor, which results from aerodynamic intake flow distortions. Extensions to the theories allow for both stationary, phase-related distortions and distortions which vary randomly with time and may therefore be considered to rotate with ...
B. Barry, C.J. Moore
openaire   +1 more source

Passive Noise Reduction for a Contra-Rotating Fan

Volume 1A: Aircraft Engine; Fans and Blowers, 2014
There 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
openaire   +4 more sources

Fan with noise reduction

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 ...
openaire   +1 more source

Low noise fan

The Journal of the Acoustical Society of America, 1995
An axial flow fan includes blades mounted on a hub and extending radially outward to a shroud disposed around the hub. Pairs of stators are connected to the shroud at positions angularly spaced about the inner periphery of the shroud. Each pair of stators includes a trailing stator angularly spaced from a leading stator by a distance related to the ...
openaire   +1 more source

Fan Compressor Noise Reduction

ASME 1969 Gas Turbine Conference and Products Show, 1969
A study of various fan/compressor noise reduction methods is presented. The analytical treatment of the basic mechanisms of fan/compressor noise generation is described. The results are presented in parametric form and indicate the effects of fan/compressor design, number of blades, vane/blade ratio, aerodynamic parameters, and blade row spacing on ...
M. J. Benzakein, S. B. Kazin
openaire   +1 more source

Characterizing computer cooling fan noise

The Journal of the Acoustical Society of America, 2003
Computer cooling fan noise is studied theoretically, focusing on the radiation from the interaction between rotor blades and motor struts. The source is decomposed into axial thrust, circumferential drag, and radial force. There is no sound-power coupling among the three components.
openaire   +4 more sources

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