Experimental and numerical investigation of noise generated by rotor blade passing an exhaust grille

This paper considers the noise generated by interaction between the rotor blade and the exhaust grille. Acoustic measurements were first performed in a semi-anechoic chamber to investigate the characteristic of the noise. An approach that combines a Reynolds averaged Navier-Stokes calculation with the stochastic noise generation and radiation method is used to identify noise sources. With the computed flow solutions, the broadband noise radiated by the grille is evaluated based on a semi-empirical noise model. The numerical results are compared with the measured noise levels and good agreement is obtained.