1999 Volume 19 Issue 74 Pages 215-222
This paper deals with noise reduction effect of partition disks on aerodynamic noise generated by curved columns in uniform air flow. The curved column is formed in Vshape by bending a straight column to an angle of 2θ. The bend part has a radius of curvature of R. Aerodynamic sounds generated by the curved columns are affected by the values of θ. When θ ?? 90°, eminent aeolian tones are generated by the curved columns. But when θ>90°, the aeolian tones are not generated, the broad band noises are generated by the curved columns. In this paper in order to decrease aeolian tones, two partition disks are attached to a bend part, and its noise reduction effect is investigated experimentally. The result shows that it becomes clear that the disks are very effective to reduce the aeolian tone. The flow visualization around the curved column with partition disks by the tuft stick method, the oil dots method and the oil film method becomes clear the mechanism of noise reduction.
