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Sound radiation from a subsonic rotor subjected to turbulence
M. Sevik
- Vol. 304, pp 493-512
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TLDR
In this paper, the broadband sound radiated by a subsonic rotor subjected to turbulence in the approach stream has been analyzed and the power spectral density of the sound intensity has been found to depend on a characteristic time scale-namely, the integral scale of the turbulence divided by the axial flow velocity-as well as several length scale ratios.Abstract:
The broadband sound radiated by a subsonic rotor subjected to turbulence in the approach stream has been analyzed. The power spectral density of the sound intensity has been found to depend on a characteristic time scale-namely, the integral scale of the turbulence divided by the axial flow velocity-as well as several length-scale ratios. These consist of the ratio of the integral scale to the acoustic wavelength, rotor radius, and blade chord. Due to the simplified model chosen, only a limited number of cascade parameters appear. Limited comparisons with experimental data indicate good agreement with predicted values.read more
Citations
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Broadband and discrete frequency radiation from subsonic rotors
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Noise of a model helicopter rotor due to ingestion of turbulence
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Book ChapterDOI
An Anechoic Facility for Basic Aeroacoustic Research
TL;DR: This chapter presents the details for the design, construction, and evaluation of a low-speed, low-turbulence, anechoic wind tunnel facility that allows for the experimental examination of an acoustic field generated by fluid/structure interaction.
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Broadband rotor noise predictions using a time domain approach
TL;DR: In this article, the broadband rotor noise can be predicted directly from measurements of turbulent velocity correlation functions upstream of a rotor without the need for turbulence modeling, using a time domain formulation and using the turbulence velocity correlation function in the plane of the rotor.
References
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Internally Generated Noise From Gas Turbine Engines. Measurement and Prediction
M. J. T. Smith,M. E. House +1 more
TL;DR: In this article, the authors defined the noise sources from gas turbine engines and their radiation patterns identified from test results, and examined single-stage and full-scale engine compressor noise measurements leads to a prediction technique being evolved for inlet and efflux levels.
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Noise From Turbojet Compressors
S. L. Bragg,R. Bridge +1 more
TL;DR: In this paper, the authors describe the characteristics of the noise and discuss possible mechanisms of generating it from the first two compressor stages of a turbojet engine during landing and suggest that some discrete tones may be eliminated over part of the running range by suitable choice of blade numbers and disposition, and that broad band noise is unlikely to be reduced without major design modifications involving either a reduction of the air speed relative to the front stage blades, or removal of the boundary layer at their trailing edges.