J.B. Schulten

The dominant sound of a turbofan engine is usually generated by rotor wakes when they impinge on a downstream stator. Consequently, to reach the intake the sound waves must pass the rotor. The rotating blades represent an obstacle that partly reflects and partly transmits the incident sound field. The present paper discusses the calculation of this process by means of a 3D lifting surface approximation of the rotor. It is shown that the reflection-transmission process can be treated as an unsteady aerodynamic problem. The method used will be illustrated by means of numerical examples. It appears that, depending on the relative angle of incidence of the sound waves, the shielding effect of the rotor can yield a reduction from negligible up to the order of 30 dB in acoustic power.

DGLR/AIAA 14th Aeroacoustics Conference, 1992

Conference Paper

englisch

21,0 x 29,7 cm, 8 Seiten

DGLR-Bericht, 1992, 1992-03, DGLR/AIAA 14th Aeroacoustics Conference - Proceedings; S.502-509; 1992; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

aeroacoustics, turbofans

Bibliothek

1992