Results from a joint DARPA/Boeing/NASA/Army wind tunnel test demonstrated the ability to reduce in-plane, low-frequency noise of the full-scale Boeing-SMART (Smart Material Actuated Rotor Technology) rotor with active flaps. Test data reported in this paper illustrated that near-field acoustic energy in the first six blade-passing harmonics could be reduced by up to 6 dB at a moderate-airspeed, level flight condition at an advance ratio of 0.30. Reduced noise levels were attributed to selective active flap schedules that modified in-plane blade airloads on the advancing side of the rotor, generating counteracting acoustic pulses that partially offset the negative pressure peaks associated with in-plane, steady thickness noise. These favorable reduced-noise operating states are a strong function of the active flap actuation amplitude, frequency, and phase. The reduced noise levels resulted in reduction of predicted aural detection distance, but incurred vibratory load penalties due to increased hub shear forces.


    Zugriff

    Zugriff über TIB

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    Reduced In-Plane, Low-Frequency Noise of an Active Flap Rotor


    Weitere Titelangaben:

    Verringerung der niederfrequenten Schallabstrahlung eines Rotors mit aktiven Klappen


    Beteiligte:
    Sim, Ben W. (Autor:in) / Janakiram, Ram D. (Autor:in) / Lau, Benton H. (Autor:in)

    Erschienen in:

    Journal of the American Helicopter Society ; 59 , 2 ; 022002/1-022002/17


    Erscheinungsdatum :

    2014


    Format / Umfang :

    1 Seite, Bilder, Tabellen, 20 Quellen




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Print


    Sprache :

    Englisch




    Reduced In-Plane, Low Frequency Noise of an Active Flap Rotor

    Sim, B. / Barbely, N. / JanakiRam, R. et al. | British Library Conference Proceedings | 2009


    Localized, Non-Harmonic Active Flap Motions for Low Frequency In-Plane Rotor Noise Reduction

    Sim, B.W. / Potsdam, M. / Kitaplioglu, C. et al. | British Library Conference Proceedings | 2012


    Study of Active Rotor Control for In-Plane Rotor Noise Reduction

    Yang, Tianxiao / Brentner, Kenneth S. / Corle, Ethan et al. | AIAA | 2018


    ROTOR STALL ALLEVIATION WITH ACTIVE GURNEY FLAP

    Bae, E.S. / Gandhi, F. / American Helicopter Society | British Library Conference Proceedings | 2013


    Correlation of SMART Active Flap Rotor Loads

    Kottapalli, S. / Straub, F. / AHS International | British Library Conference Proceedings | 2009