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A numerical study on the aerodynamic noise generation of a high efficiency propeller is carried out.

Three-dimensional numerical simulation based on Reynolds averaged N-S model is performed to obtain the aerodynamic performance of the propeller. Then, the result of the aerodynamic analysis is given as input of the acoustic calculation. The sound is calculated using the Farassat 1A which was derived from Ffowcs Williams–Hawkings equation and is compared with the measurements.

Moreover, the fan is modified for noise reduction by changing its geometrical parameters such as span, chord length and torsion angle.

The variation trend of aerodynamic and acoustic are compared and discussed for different modification tasks. Some meaningful conclusions are drawn on the noise reduction of propeller.

The purpose of this paper is to reduce the acoustic noise of helicopter ducted tail rotor.

To predict the noise accurately, a thin-body boundary element method (BEM)/Ffowcs Williams–Hawkings method is developed in this paper. It is a hybrid method combining the BEM with computational aeroacoustics and can be used efficiently to predict the propagation of sound wave in the duct.

Compared with the experimental results, the proposed method of acoustic noise is rather desirable.

Then several geometry parameters are modified to investigate the noise reduction of ducted tail rotor by using the numerical prediction method.

The aerodynamic and acoustic performance of different modification tasks is discussed. These results demonstrate the validity of design parameters modification of ducted tail rotor in acoustic noise reduction.