A numerical simulation of noise generation during closed-loop vibration reduction using actively controlled flaps (ACFs) has been conducted. To develop this simulation capability, a rotor aerodynamic model generating unsteady time-domain blade surface pressure distributions and including effects of compressibility and a free-wake was developed. This aerodynamic tool was incorporated into an aeroelastic model featuring fully coupled flap-lag-torsional dynamics and including moderate deflections. An acoustic prediction tool based on WOPWOP was also introduced and modified to fully account for blade flexibility on noise generation. This unified aeroelastic/aeroacoustic analysis program was validated with experimental aerodynamic and acoustic data. Single and dual ACF configurations were used to reduce 4/rev vibrations in descending flight, where heavy blade-vortex interaction (BVI) effects are expected, and the accompanying changes to noise generation were carefully examined. It was observed that noise on a carpet plane beneath the rotor increases by 1-3 dB for all ACF vibration reduction configurations simulated. However, imposing saturation limits on flap deflections and using the dual flap configuration was found to reduce the acoustic penalty as a result of vibration reduction.


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    Title :

    Rotorcraft vibration reduction and noise prediction using a unified aeroelastic response simulation


    Additional title:

    Schwingungsreduzierung bei Hubschraubern und Lärmvorhersage durch Simulation der aeroelastischen Impulsantwort


    Contributors:
    Patt, Dan (author) / Liu, Li (author) / Friedmann, Peretz P. (author)

    Published in:

    Publication date :

    2005


    Size :

    12 Seiten, 15 Bilder, 3 Tabellen, 53 Quellen




    Type of media :

    Article (Journal)


    Type of material :

    Print


    Language :

    English





    ROTORCRAFT VIBRATION REDUCTION AND NOISE PREDICTION USING A UNIFIED AEROELASTIC RESPONSE SIMULATION

    Patt, D. / Liu, L. / Friedmann, P. P. et al. | British Library Conference Proceedings | 2003


    Rotorcraft Vibration and Noise Prediction Using a Unified Aeroelastic Analysis

    Friedmann, P. / Liu, L. / Patt, D. et al. | British Library Conference Proceedings | 2003


    Rotorcraft Vibration and Noise Prediction Using a Unified Aeroelastic Analysis

    Friedmann, Peretz / Liu, Li / Patt, Dan | AIAA | 2003


    Simultaneous Vibration and Noise Reduction in Rotorcraft Using Aeroelastic Simulation

    Liu, L. / Patt, D. / Friedmann, P. P. et al. | British Library Conference Proceedings | 2004