An anechoic wind tunnel experiment was conducted to determine the effects of simulated flight on the noise characteristics of a high throat Mach number fan inlet. Comparisons were made with the performance of a conventional low throat Mach number inlet with the same 50.8 cm fan noise source. Simulated forward velocity of 41 m/sec reduced perceived noise levels for both inlets, the largest effect being more than 3 db for the high throat Mach number inlet. The high throat Mach number inlet was as much as 7.5 db quieter than the low throat Mach number inlet with tunnel airflow and about 6 db quieter without tunnel airflow. Effects of inlet flow angles up to 30 deg were seemingly irregular and difficult to characterize because of the complex flow fields and generally small noise variations. Some modifications of tones and directivity at blade passage harmonics resulting from inlet flow angle variation were noted.


    Access

    Access via TIB

    Check availability in my library


    Export, share and cite



    Title :

    Simulated flight effects on noise characteristics of a fan inlet with high throat Mach number


    Contributors:

    Publication date :

    1978-04-01


    Type of media :

    Report


    Type of material :

    No indication


    Language :

    English




    Simulated flight effects on noise characteristics of a fan inlet with high throat mach number

    Wesoky, Howard L. / Dietrich, Donald A. / Abbott, John M. | TIBKAT | 1978




    Extending the Flight Mach Number of the SR-71 Inlet

    Colville, Jesse / Starkey, Ryan / Lewis, Mark | AIAA | 2005


    Inlet Geometry and Axial Mach Number Effects on Fan Noise Propagation

    Nagamatsu, Henry T. / O'keefe, Jack V. / Schwartz, Ira R. | AIAA | 1975