Results 271 to 280 of about 11,859 (310)

Aerodynamic Noise from Vehicles

The Journal of the Acoustical Society of America, 1973
The sources of vehicle noise and their importance relative to aerodynamic noise is given. Using the theory of Lighthill, a summary is given of aerodynamic noise theory and experiment. Following a review of the literature on axial and propeller fan noise and on vehicle cooling fan noise, the present state of the art is described, including present noise
Robert C. Chanaud, Douglas Muster
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Aerodynamic Noise in Supersonic Wind Tunnels

Journal of the Aerospace Sciences, 1961
Hot-wire measurements in the free stream of a supersonic wind tunnel were made in the Mach number range of 1.6 to 5.0. I t is shown that the mass-flow fluctuations increase very rapidly with increasing Mach number. If the fluctuation field is assumed to consist of sound waves—an assumption tha t is consistent with the measurements—the sound intensity ...
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A SURVEY OF AERODYNAMIC NOISE

1964
Abstract : A representative survey of the literature of aerodynamic noise was made. This was not intended to be an exhaustive list but rather to give the state of the field presently. It was found that much of the research done in this field is either experimental or semi-empirical.
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The theoretical modelling of aerodynamic noise

Proceedings of the Indian Academy of Sciences Section C: Engineering Sciences, 1978
This paper is a review of the present state of understanding of aerodynamically generated noise.
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Aerodynamic Noise and the Plane Boundary

The Journal of the Acoustical Society of America, 1960
In an earlier paper entitled “Thoughts on Boundary Layer Noise” (Aeronautical Research Council Report 16727, 1954), it was pointed out that while the fluctuating pressures exerted upon a rigid boundary by a contiguous unsteady flow can be shown in a formal manner to generate sound as of a distribution of dipoles, it can be argued by means of the ...
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Lighthill’s Theory of Aerodynamic Noise

2012
In 1952, Lighthill [61] gave the first formulation of aerodynamic sound, which is based on an analogy of sound radiated by fluctuating monopole, dipole, or quadrupole sound sources. Lighthill’s treatment of the subject will be discussed in this chapter, which starts with a derivation of an equation of sound.
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Aircraft Aerodynamic Noise Measurement

2007
Aircraft noise in flight is mostly produced from propulsion system (engine and propeller, for propeller driven aircraft), but one part of the noise come from air stream over aircraft surfaces (wings, airframe etc) – it is aerodynamic or airframe noise.
Domitrović, Anita, Bazijanac, Ernest, Franjković, Davor   +2 more
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Remarks on the theory of aerodynamic noise

The Journal of the Acoustical Society of America, 1975
Lighthill's theory of aerodynamic noise has been the foundation of the current noise research. The theory is exact and based on an acoustic analogy. The source strength, however, can be found only when the problem is solved. To make a quantitative calculation, one has to make various approximations to the theory.
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Measurement and Evaluation of Aerodynamic Noise

SAE Technical Paper Series, 1999
<div class="htmlview paragraph">Recently, aerodynamic noise which originates in the flow of the body surroundings is actualized as a main cause of an automobile interior noise when running at high speed, because engine, power train and tire noise have been greatly decreased. Along with it, the measurement technology for the phenomenon elucidation
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Further Topics in Aerodynamic Noise

2012
In principle, the convected quadrupole theory, as developed by Ffowcs-Williams, can be used also for supersonic jet noise. However, subsonic jet noise, where no complex phenomena such as shock or screeching noise exist, is based mainly on turbulent mixing.
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