著者

岡島 厚 大津山 澄明 永森 稔朗 中野 智仁 木綿 隆弘

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. B編 (ISSN:03875016)

巻号頁・発行日

vol.65, no.635, pp.2196-2203, 1999-07-25

被引用文献数

19

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Flow induced in-line oscillation of a structure with a circular or rectangular section was experimentally studied by free-oscillation tests in a wind tunnel. Detailed data of response amplitude of various cylinders have been acquired in a wide range of the reduced mass-damping parameter (Scruton number), by free-oscillation tests of two-dimensional cylinder spring-mounted to oscillate as a rigid cylinder. Flow induced in-line oscillation of the cylinder is certified to have two types of excitation mechanism; one is the so-called wake breathing effect accompanied with a symmetric vortex street and the other is the vortex excitation at a half of the critical reduced velocity. Also a fixed splitter plate was mounted behind a cylinder to eliminate the vortex shedding of alternate vortices from the cylinder, after Aguirre's experiments, and the results were compared with those without a splitter plate. As a result, we can classify the flow induced in line oscillation of the circular or rectangular cylinder. For a circular cylinder and a square one, two types of excitation phenomena appear in each reduced velocity region, the thin rectangular cylinder with the side ratio b/h=0.4 suffers from the vortex excitation, and the elongated rectangular cylinder with the side ratio b/h=2.5, is subjected to the wake breathing effect accompanied with a symmetric vortex street. It is found that fluidelastic characteristics of two types of in-line oscillations are quite different; i.e., the response amplitude are very sensitive to the reduced massdamping parameter, during the in line oscillation with a symmetric vortex street, while the oscillation of vortex excitation are rather insensitive.