Aerodynamic sound generated by the collision of a vortex pair with a corner

Abstract

This study investigates the mechanisms of the aerodynamic sound emitted by the collision of a vortex pair with a corner. When the vortex pair collides with the corner of a wall at a 45° angle of incidence, a reflection-symmetric vortex motion is observed, relatively strong vortices are generated on the wall, and the primary aerodynamic sound is generated. Subsequently, the vortex pair collides repetitively with the corner of the wall several times, which generates negligible aerodynamic sound. In contrast, when the angle of incidence is greater than 45°, non-reflection-symmetric vortex motion is observed. After the first collision of the vortex pair with the corner, complex vortex deformation and coalescence are observed. In this case, aerodynamic sound is generated by both the first wall collision and the complex vortex deformation and coalescence. This study also identifies that the vortex motion and aerodynamic sound generated by a vortex pair colliding with a wall corner depends on the angle of incidence. Although a precise comparison cannot be made, the maximum aerodynamic sound is observed when the angle of incidence is approximately 60°. The results of this study indicate that aerodynamic sound can be reduced by controlling the angle of incidence of the collision of the vortex pair with the corner.

Keywords

• aeroacoustics
• computational fluid dynamics
• vortex sound
• vortex
• vortex pair