Abstract
To investigate the generation mechanism of tonal-noise from a rear-view mirror, tonal-noise radiated from the backward-facing step with surface bump was measured with a low-noise wind tunnel. Noise level of tonal noise depended on the distance between the trailing-edge of the bump and the edge of the backward-facing step. The frequency of the tonal-noise can be estimated with the prediction model based on the characteristics time of sound propagation and vorticity convection. The predicted frequencies were in good agreement with the experimental ones.
