Abstract
To reduce the aerodynamic tonal-noise from rearview mirrors, active flow control techniques were utilized with oscillating jets on the surface of rear-view mirror. The experimental results showed the noise reduction level depended on the frequency and intensity of the oscillating jets. The noise reduction level was 20 dB at the oscillation frequency about 400Hz and the jet velocity about 0.1 m/s. Both of the frequency and intensity of the jet were smaller than the frequency of the feedback noise and the uniform flow velocity. These results indicated that the oscillating jets effectively reduced aerodynamic noise with small amount of energy.
