Hayashi H., Kodama Y., Fukano T.

The aeolian tones generated from the tapered cylinder were investigated for several swept angles experimentally. The diameter of the tapered cylinder is varied from 10 mm to 40mm in the span-direction and the tapered angle is 5 degree. The tapered cylinder is set with various swept angles. The zero swept angle is defined the cylinder set in normal to the uniform flow direction. It is obtained some interesting characteristics in relating to the aeolian tone and its sources of the swept cylinder. The aeolian tone is large not at the zero swept angle, that is, the two-dimensional flow condition, but at about -30 and 30 degrees. When the swept angle is �E0 degree, that is, the side of the large diameter is set upstream, the aeolian tone becomes large compared with the case of the opposite setting of the swept angle. The velocity fluctuation of the unsteady flow near the trailing edge has peak in spectrum distribution. At the case of the zero swept angle, the peak frequency is almost constant in about 70% of span length, even though the diameter varied in span direction. The peak frequency is corresponding to the Strouhal Number of large side diameter. The frequency near the small diameter side gradually increased toward to the endplate. At the case of swept cylinder, the peak frequency of the velocity fluctuation varies in span direction. The peak level of the fluctuating velocity is large at the zero swept angle near the middle of span compared with the case of the -30 or 30 degrees. But the aeolian tone level of zero swept angle is low compared with the case of -30 and 30 degrees. It is indicate that the aeolian tone is not governed with the strength of the flow fluctuation in the wake.