Aerodynamic Sounds Generated by Curved Columns in a Uniform Air Flow.

This paper deals with aerodynamic sounds generated by the curved columns in a uniform air flow experimentally. The curved column is formed in V-shape by bending a straight column to an angle of 2θ. The angle θ means the angle between the direction of air flow and a one-sided straight part of V-shaped column. The bend part has a radius of curvature of R. In the experiment, the effects of θ's and R's on the aerodynamic sound have been examined in detail. The results of the frequency analyses of aerodynamic sounds show that when θ≤90°, eminent aeolian tones are generated by the curved columns and moreover, that the peak frequencies of aeolian tones are affected by the values of R and θ. However, when θ > 90°aeolian tones are not generated but whistling noises generated in a broad frequency range.