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.
Rotorcraft vibration reduction and noise prediction using a unified aeroelastic response simulation
Schwingungsreduzierung bei Hubschraubern und Lärmvorhersage durch Simulation der aeroelastischen Impulsantwort
Journal of the American Helicopter Society ; 50 , 1 ; 95-106
2005
12 Seiten, 15 Bilder, 3 Tabellen, 53 Quellen
Aufsatz (Zeitschrift)
Englisch
ROTORCRAFT VIBRATION REDUCTION AND NOISE PREDICTION USING A UNIFIED AEROELASTIC RESPONSE SIMULATION
British Library Conference Proceedings | 2003
|Rotorcraft Vibration Reduction and Noise Prediction Using a Unified Aeroelastic Response Simulation
Online Contents | 2005
|Rotorcraft Vibration and Noise Prediction Using a Unified Aeroelastic Analysis
British Library Conference Proceedings | 2003
|Simultaneous Vibration and Noise Reduction in Rotorcraft Using Aeroelastic Simulation
British Library Conference Proceedings | 2004
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