This paper reports new analysis and prediction development of rotor broadband noise. The two primary components of this noise are blade-wake interaction (BWI) noise, due to the blades' interaction with the turbulent wakes of the preceding blades, and 'Self' noise, due to the development and shedding of turbulence within the blades' boundary layers. Emphasized in this report is new modelling and code development for rotor blade self noise. The analysis and validation employs data from the HART program, a model BO-105 rotor test conducted in the German-Dutch Wind Tunnel (DNW). The BWI noise predictions are based on measured pressure response coherence functions using cross-spectral methods. The self noise predictions are based on previously reported semi-empirical modelling obtained from isolated airfoil sections but include new modelling and code developments for higher speeds, inclusion of all Doppler effects and capability to define performance and local blade segment flow conditions and positions from advanced comprehensive rotorcraft analysis such as CAMRAD.Mod1. Both BWI and self noise from individual blade segments are now Doppler shifted and summed at the observer positions. Prediction comparisons with measurements show good agreement for a range of rotor operating conditions from climb to steep descent. The broadband noise predictions, along with those of harmonic and impulsive Blade-Vortex Interaction (BVI) noise predictions, demonstrate a significant advance in predictive capability for main rotor noise.
Rotor broadband noise prediction with comparison to model data
Vorhersage der breitbandigen Rotorgeräuschemission und Vergleich mit Modelldaten
Journal of the American Helicopter Society ; 49 , 1 ; 28-42
2004
15 Seiten, 17 Bilder, 52 Quellen
Aufsatz (Zeitschrift)
Englisch
Rotor Broadband Noise Prediction with Comparison to Model Data
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