G204 空力音の発生に対する主流乱れの影響(2)(GS2 空力音,音響,音波,一般セッション)

概要

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In order to clarify the effect of uniform flow turbulence, aerodynamic sound and static pressure fields were measured in a low-noise wind tunnel with an active turbulence generator. The experimental results showed that it is important the eddy scale of the uniform flow rather than turbulent intensity for aerodynamic sound generation. The spanwise coherence length of circular cylinder depended on the scale of incoming flow. Since the spanwise scale decreased in the large-scale turbulent field, as a result, resultant aerodynamic sound also decreased. It indicated that the eddy scale of the uniform flow, L, and the diameter of cylinder, D, were dominant parameters for aerodynamic sound generation in turbulent flow fields. The phase averaged static pressure fields were also measured. Asymmetric vortex street as Karman vortex clearly observed at L/D = 0.4. After that, Karman vortex disappeared when the eddy scale of uniform flow were almost the same as the diameter of the cylinder. The experimental results showed that the level of aerodynamic sound depend on the structure of the wake which depended on the scale of uniform flow.
一般社団法人日本機械学会の論文
2007-11-17