The noise emitted by the interaction of a turbulent jet with an airfoil is considered. The incoming-turbulence noise mechanism is assumed to be the dominant noise source. Amiet's broadband noise theory is combined with a semi-empirical description of the turbulent field. The turbulence characteristics of the transitional shear layer are obtained from particle image velocimetry measurements. The turbulence energy spectra are found to compare well with Liepmann's isotropic model. This model is combined with Amiet's theory to predict the noise that would be emitted by a 1-meter span airfoil uniformly submitted to a turbulence with the same characteristics as found in the jet. The noise generated by turbulent flow around airfoils is an environmental concern in aerospace industry for high-lift devices and in applications such as cooling fans or wind turbines. The process of broadband noise generation by turbulence interacting with a solid surface has been recognized since the early ages of aeroacoustics. One distinguishes three basic mechanisms of broadband noise generation by an airfoil: incoming-turbulence noise, self-noise, and vortex-shedding noise.
Aerodynamic noise generated by an airfoil in a turbulent jet flow
Aerodynamisches Geräusch, erzeugt durch einen Tragflügel in einer turbulenten Strahlströmung
2005
8 Seiten, 7 Bilder, 6 Quellen
Conference paper
Storage medium
English
Numerical Prediction of Airfoil Aerodynamic Noise
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