Flyover and static noise data from several engines are presented that show inlet fan noise measured in flight can be lower than that projected from static tests for some engines. The differences between flight and static measurements appear greatest when the fan fundamental tone due to rotor-stator interaction or to the rotor-alone field is below cutoff. Data from engine and fan tests involving inlet treatment on the walls only are presented that show the attenuation from this treatment is substantially larger than expected from previous theories or flow duct experience. Data showing noise shielding effects due to the location of the engine on the airplane are also presented. These observations suggest that multiringed inlets may not be necessary to achieve the desired noise reduction in many applications.


    Access

    Access via TIB

    Check availability in my library


    Export, share and cite



    Title :

    Effects of forward velocity and acoustic treatment on inlet fan noise


    Contributors:

    Conference:

    Aircraft Design, Flight Test and Operations Meeting ; 1974 ; Los Angeles, CA


    Publication date :

    1974-08-01


    Type of media :

    Conference paper


    Type of material :

    No indication


    Language :

    English






    Inlet Acoustic Treatment for Interior Noise Control

    Burd, D. / Eversman, W. / Dandaroy, I. et al. | British Library Conference Proceedings | 2007



    Inlet Acoustic Treatment for Interior Noise Control

    Burd, David / Eversman, Walter / Dandaroy, Indranil | AIAA | 2007