1. Jet Noise Reduction by Induced Flow.
- Author
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Dyer, Ira, Franken, Peter A., and Westervelt, Peter J.
- Abstract
The effect on the generation of jet noise by the secondary air induction of a modified jet nozzle is analyzed. It is shown that the combination of the secondary air with the primary jet air creates a new jet stream of larger area, lower velocity, and lower noise generation. The decrease in noise radiation is found in terms of the area of the combined jet stream. Detailed check of the theory is not possible at present because measurements of the areas of the combined jet streams have not been generally made along with measurements of the noise. However, it is possible to estimate the upper limit of the appropriate jet stream area in order to obtain the upper limit on noise reduction. The upper limit on noise reduction obtained from the theory is consistent with existing measurements. Qualitative conclusions from the theory with respect to the spectrum and directivity of the noise radiated by jets with modified nozzles are in accord with measurements. [ABSTRACT FROM AUTHOR]
- Published
- 1958
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