2002 Fiscal Year Final Research Report Summary
MECHANISM OF VIBRATION SUPPRESSION EFFECT FOR CONNECTED CANTILEVERED STRUCTURE OSCILLATING IN-LINE DIRECTION IN CROSS FLOW
| Project/Area Number |
12450094
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Dynamics/Control
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KANEKO Shigehiko GRADUATE SCHOOL OF ENGINEERING, PROFESSOR, 大学院・工学系研究科, 教授 (70143378)
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| Co-Investigator(Kenkyū-buntansha) |
SAITOU Noboru TOSHIBA CO., RESEARCH DIRECTOR, 電力産業システム技術開発センター, 室長(研究職)
WATANABE Tatsuo GRADUATE SCHOOL OF ENGINEERING, Research Associate, 大学院・工学系研究科, 助手 (70011179)
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| Project Period (FY) |
2000 – 2002
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| Keywords | FLOW-INDUCED VIBRATION / SELF-EXCITED VIBRATION / ANTI-SYMMETRIC VOTICES / IN-LINE OSCILLATION / KARMAN VORTICES / SYMMETRIC VOTICES / DRAG FORCE / VORTEX SHEDDING |
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| Research Abstract |
This study is related to self-excited in-line vibration of a thermo-well in liquid sodium cross flow experienced in Fast Breeder Reactor Monju. Although quite a large number of research on the in-line oscillation of a cantilevered cylinder have been conducted in Japan after the failure of the thermo-well, clear cut explanation of the cause of the vibration has not yet been done. Especially, the explanation on the reason why only single particular thermo-well was broken is not yet given and is still under investigation. From the viewpoint of academic interest, this is an exciting topic.
Therefore, we decided, to conduct precise measurement of fluid dynamic forces acting on the vibrating cylinder by using water tunnel at CRIERI Abiko Research Center under small forcing amplitude external excitations. In a series of experiments, we changed forcing amplitudes, oncoming flow velocities and excitation frequencies to check the effect of the dependency on the amplitude of the cylinder and reduced velocity.
As a result, we found the fact that fluid force is composed of the component proportional to acceleration, velocity and displacement of the vibrating circular cylinder. We also found that excitation parameter which determines the instability is strongly dependent on the cylinder amplitude. In addition, added mass coefficient varies depending on reduced velocity and the stability criteria of reduced damping is slightly affected by the mass ratio. Finally, we collected unsteady fluid dynamic data as a database for further studies.
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Research Products
(12 results)
