Preliminary engineering designs of nacelle acoustical treatments applicable to jet transports have been studied to suppress compressor noise; concepts involved application of narrow-band resonators and wide-band acoustical absorbers to walls of fan-discharge and inlet ducts; broadband resonator concept for duct lining was developed; tests evaluated inlets with light-bulb-shaped centerbodies to provide narrower duct dimensions and increased surface area; tests determined flow resistance and absorption coefficient of various duct-lining treatment configurations; inlet and fan-discharge duct lining design recommendations for JT3D engine series are made which use broadband resonator concept. (06906)


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    Title :

    Study of turbofan-engine compressor-noise-suppression techniques


    Additional title:

    NASA CR


    Contributors:
    Marsh, A.H. (author) / Elias, I. (author) / Hoehne, J.C. (author) / Frasca, R.L. (author)

    Published in:

    Publication date :

    1968


    Size :

    174 pages


    Type of media :

    Report


    Type of material :

    Print


    Language :

    English





    A Study of Turbofan-Engine Compressor-Noise- Suppression Techniques

    I. Elias / R. L. Frasca / J. C. Hoehne et al. | NTIS | 1968


    A study of turbofan-engine compressor noise suppression techniques

    Elias, I. / Frasca, R. L. / Hoehne, J. C. et al. | NTRS | 1968


    Turbofan-engine noise suppression

    MARSH, A. | AIAA | 1967


    Turbofan-engine noise suppression.

    MARSH, A. H. | AIAA | 1968