気流中の角柱列から発生する異音の低減

抄録

In the present paper the attention is focused on reduction of strange noise generated from rectangular cylinders in cross flow. The width-to-height ratios of was 3.0. The tube pitch ratio in the transverse direction was 8.0. We measured the aerodynamic sound radiated from the rectangular cylinders in the range of Reynolds numbers from about 10³ to 10⁴. The several high peaks were formed at the spectrum of SPL. The two peaks of the spectrum of Strouhal number of 0.08 and 0.2 were caused by vortex shedding from the two horizontal rails of 16×30 mm and rectangular cylinders of 5×15 mm, respectively. On the other hand, the strange noise occurred at five times the vortex shedding frequency. This noise is caused by the vibration excited by the vortex shedding at the natural frequency. We have discussed how to counteract the noise generated by rectangular cylinders.