J.C. Simonich, P.L. Lavrich, T.G. Sofrin

A proof of concept experiment has been performed which shows the potential for active aerodynamic control of rotor wake/stator interaction noise in a simplified manner. A single airfoil model representing the stator was fitted with a moveable trailing edge flap controlled by a servo motor. This flap allowed control of the unsteady lift of the airfoil and acted as the active aerodynamic element in the system. Upstream of the airfoil, a disturbance generator created a periodic wake, similar to an actual rotor blade wake, which impinged on the airfoil. A control system moved the motor driven flap in the correct angular displacement rate and phase to reduce the unsteady load on the airfoil during the wake interaction. The motion could be arbitrary permitting the airfoil-flap combination to respond to generic inflow disturbances. Noise reduction results showed that this concept works very well in the bandwidth at which the servo motor drive actuated the flap (currently up to 100 Hz). The peak-to-peak acoustic interaction pulse was reduced by a factor of two, while the corresponding noise was reduced by a significant 10 dB for specific harmonics. A companion paper by E. J. Kerschen, entitled Active Aerodynamic Control of Wake-Airfoil Interaction Noise - Theory, demonstrates the ability to predict the required flap motion to achieve these dramatic noise reductions.

DGLR/AIAA 14th Aeroacoustics Conference, 1992

Conference Paper

englisch

21,0 x 29,7 cm, 9 Seiten

DGLR-Bericht, 1992, 1992-03, DGLR/AIAA 14th Aeroacoustics Conference - Proceedings; S.229-237; 1992; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

aeroacoustics

Bibliothek

1992