Measurements of Aero-Acoustic Noise and Pressure Fluctuation Generated by a Door-Mirror Model Placed on a Flat Plate

In order to provide reliable validation data for computational aeroacoustics methods that predict bluff-body sound, far-field sound pressure and fluctuating surface pressure are measured in detail for a simplified model of a rear-view mirror for use in automobiles. The surface flow on the model is also visualized by oil flow method. The model is composed of a quarter-part sphere mounted on the top of a half-circular cylinder that is placed on a flat plate and is expected to reproduce important features of the flow around an actual rear-view mirror. The Reynolds number based on the upstream uniform wind velocity and the diameter of the half-circular cylinder is varied from 1.4 × 105 to 2.4 × 105 for model yaw angles of 0 degrees and 15 degrees. Based on the measured results, the separation and transition of the boundary layer that develops on the model surface are discussed together with the large-scale structures in the flow around the model. Characteristics of the aerodynamic sound that radiates from the door-mirror model are also discussed in relation to those flow structures.