| Project/Area Number |
10650156
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fluid engineering
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| Research Institution | Kitami Institute of Technology |
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Principal Investigator |
SAKAMOTO Hiroshi Kitami Institute of Technology, Professor, 工学部, 教授 (70003176)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAI Kazunori Kitami Institute of Technology, Researcher, 工学部, 教務職員 (50271755)
HANIU Hiroyuki Kitami Institute of Technology, Professor, 工学部, 教授 (70172955)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1999: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1998: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Forced vibration / Free vibration / Rectangular prism / Flow-Induced vibration / Feedback Mechanism / Response characteristics of Oscillation / Suppration of Flow-Induced vibration / Flutter phenomenon / 流体・構造体連成振動 / 自由振動実験 / 低風速フラッタ / 渦励振 / 高風速フラッタ / 空力振動の制御 / T字型制御物体 / 強制振動実験 / 渦励振現象 / 低速フラッタ現象 / 高速フラッタ現象 / ダンピング特性 |
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| Research Abstract |
The objective of this study to investigate the feedback mechanism of combined vibration phenomenon of fluid-structure and its control. The rectangular prism with various ratio of depth having a fundamental structure configuration is adopted. The response characteristics of rotary oscillation of the rectangular prism are investigated on the free and forced vibration test. The suppression of the flow-induced vibrations is established by a T-shape plate and a splitter plate attached to the upstream and downstream of rectangular prism. The main results can be summarized as follows.
(1) The fluctuating pressure on side surface of the prism except near the trailing edge is generated by impinging leading-edge vortex shed periodically from the leading edge of the prism.
(2) Flow-induced vibrations of a prism with B/H=3 is induced by impinging leading-edge vortex and wake vortices. The T-shape plate suppresses the generation of impinging leading-edge vortex and the splitter plate suppresses the g
… More
eneration of the wake vortices.
(3) The fluctuating moment of the prism with splitter plate is almost same to the plain prism. However, the fluctuating moment of the prism with T-shape plate greatly decreases in comparison with the plain prism. Therefore, it is recognized that flow-induced vibrations of the prism are strongly dependent on the impinging leading-edge vortices rather than the wake vortices.
(4) The work done by fluctuating moment of the plain prism and the prism with splitter plate becomes a positive within forced oscillation frequency Sv<1.0 and flow-induced vibration diverges. On the other hand, the work of the prism with T-shape plate becomes almost zero value in the range of Sv=0 to 0.06. And the vibration converges because the work is negative in the range to Sv=0.23.
(5) From the free-vibration test for the plain rectangular prism with impinging leading-edge vortices, it is found that there exists three types of flow-induced vibration, I.e., low-speed torsion flutter, vortex excitation and high-speed torsion flutter.
(6) The vortex excitation is suppressed when the splitter plate is attached at the downstream of a prism. The low-speed and the high-speed torsion flutter and the vortex excitation are suppressed when the T-shape plate is attached at the upstream side. Therefore, suppression of the flow-induced vibrations of the prism is done with the most effectiveness when the impinging leading-edge vortices are suppressed with the T-shape plate. Less
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