Proceedings ArticleDOI
Experimental investigation of surface roughness generated flow noise
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The article was published on 1983-04-11. It has received 27 citations till now. The article focuses on the topics: Surface roughness & Hydraulic roughness.read more
Citations
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Journal ArticleDOI
Porous airfoils: noise reduction and boundary layer effects
TL;DR: In this paper, the boundary layer properties of porous airfoils and the noise generated at the trailing edge were analyzed using a planar 56-channel microphone array and the boundary layers were measured using constant temperature anemometry.
Journal ArticleDOI
Circular cylinders with soft porous cover for flow noise reduction
Thomas F. Geyer,Ennes Sarradj +1 more
TL;DR: In this article, a small aeroacoustic wind tunnel on a set of circular cylinders with a soft porous cover was used to investigate the possible reduction of noise from struts and other protruding parts.
Journal ArticleDOI
The far-field sound from rough-wall boundary layers
TL;DR: In this article, the noise radiated by a turbulent boundary layer over a rough wall is characterized by a dipole surface source that, if the surface pressure is spatially homogeneous, can be specified b...
Dissertation
A Study of Bio-Inspired Canopies for the Reduction of Roughness Noise
TL;DR: In this paper, the authors take inspiration from the structure of the down covering the flight feathers of larger species of owls, which contributes to their ability to fly almost silently at frequencies above 1.6 kHz.
Journal ArticleDOI
The Turbulent Boundary-Layer Rough-Wall Pressure Spectrum at Acoustic and Subconvective Wavenumbers
TL;DR: The rough-wall turbulent boundary-layer wall pressure spectrum differs from that on a smooth wall because the strength of the turbulence Reynolds stresses responsible for the pressure fluctuations are increased by surface roughness, and because the near fields of those enhanced pressure sources are redistributed in wavenumber by diffraction by the roughness elements.
References
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Journal ArticleDOI
On Sound Generated Aerodynamically. I. General Theory
TL;DR: In this paper, a theory for estimating the sound radiated from a fluid flow, with rigid boundaries, which as a result of instability contains regular fluctuations or turbulence is initiated, based on the equations of motion of a gas.
Journal ArticleDOI
The Influence of Solid Boundaries upon Aerodynamic Sound
TL;DR: In this paper, an extension to Lighthill's general theory of aerodynamic sound was made to incorporate the influence of solid boundaries upon the sound field, and it was shown that these effects are exactly equivalent to a distribution of dipoles, each representing the force with which unit area of solid boundary acts upon the fluid.
Journal ArticleDOI
Measurements of the fluctuating pressure at the wall beneath a thick turbulent boundary layer
TL;DR: In this article, the authors measured the turbulent pressure field at the wall beneath a thick (5-inch) turbulent boundary layer produced by natural transition on a smooth surface and found that the root-mean-square wall pressure was 2.19 times the wall shear stress.
Journal ArticleDOI
Aerodynamic Noise and the Plane Boundary
TL;DR: In this article, the image principle is developed in a rigorous manner and the apparent paradox is resolved with the help of an extension of Lighthill's and Curle's analyses to include boundaries which are not wholly immersed in the noise generating flow.
Journal ArticleDOI
Resolution and structure of the wall pressure field beneath a turbulent boundary layer
W. W. Willmarth,F. W. Roos +1 more
TL;DR: The power spectrum of the wall pressure that would be measured by a transducer of vanishingly small size and the corrections to the power spectra measured by finite-size transducers were determined from the spectra of four transducers of different diameters as discussed by the authors.