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Noise generated by airfoil profiles placed in a uniform laminar flow

Published online by Cambridge University Press:  20 April 2006

H. Arbey
Affiliation:
Laboratoire de Mécanique des Fluides, associé au CNRS. Ecole Centrale de Lyon, 69130 Ecully, France
J. Bataille
Affiliation:
Laboratoire de Mécanique des Fluides, associé au CNRS. Ecole Centrale de Lyon, 69130 Ecully, France

Abstract

The present paper is devoted to the experimental study of the noise generated by an airfoil profile placed in a uniform laminar flow. The far-field acoustic spectrum is shown to be composed of a broadband contribution around frequency fs and a discrete contribution at equidistant frequencies fn, which follow power laws of the forms fsU1.5 and fnU0.85. Both contributions can be accounted for by a simple model derived from the original suggestions of Tam (1974) and Fink (1975). It is essentially assumed that the diffraction of the Tollmien-Schlichting instabilities by the trailing edge generates acoustic waves which propagate in the far field and also trigger an aeroacoustic feedback loop, whose length is equal to the distance between the trailing edge and the maximum velocity point of the airfoil.

Type
Research Article
Copyright
© 1983 Cambridge University Press

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