Measurements on helicopters in flight have been performed in order to improve the noise characteristics used in computer simulations of helicopter noise. A new method of deriving a three-dimensional directivity pattern of the noise source from the measurements is presented. The method is based on a fit of the measured data to spherical harmonics. Using these models, the sound emission for different flight procedures is investigated and compared to measured data. The novel three-dimensional model allows significantly improved sound simulation accuracy.
Modeling of three-dimensional sound directivity patterns of helicopters
Modellierung der drei-dimensionalen Schallrichtmuster von Helicoptern
Acta Acustica united with Acustica ; 89 , 2 ; 273-279
2003
7 Seiten, 6 Bilder, 4 Tabellen, 21 Quellen
Article (Journal)
English
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