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Results from cascade thrust reverser noise and suppression experimentsResults from experimental work on model scale cascade reversers with cold airflow are presented. Sound power level directivity and spectral characteristics for cascade reversers are reported. Effect of cascade exit area ratio, vane profile shape, and emission arc are discussed. Model equivalent diameters varied from 3 to 5 inches, pressure ratios range from 1.15 to 3.0. Depending on the reverser type, acoustic power was proportional to the 4 1/2 to 6th power of ideal jet velocity. Reverser noise peaked at higher frequency and was more omnidirectional than nozzle-alone jet noise. Appreciable reduction in sideline noise was obtained from plane shields. Airfoil-vaned cascades were the most aerodynamically efficient and least noisy reversers. Scaling of cascade reverser data to example aircraft engines showed all cascades above the 95 PNdB sideline goal from STOL aircraft. However, the airfoil-vaned reverser has a good potential for meeting this goal for high-bypass (low pressure ratio) exhausts.
Document ID
19740009391
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Gutierrez, O. A. (NASA Lewis Research Center Cleveland, OH, United States)
Stone, J. R. (NASA Lewis Research Center Cleveland, OH, United States)
Friedman, R. (NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 3, 2013
Publication Date
January 1, 1974
Subject Category
Propulsion Systems
Report/Patent Number
E-7864
NASA-TM-X-71500
Meeting Information
Meeting: Aerospace Sci. Meeting
Location: Washington, DC
Country: United States
Start Date: January 30, 1974
End Date: February 1, 1974
Sponsors: AIAA
Accession Number
74N17504
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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