| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2001: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2000: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Research Abstract |
The objective of this study is investigated the suppression of generation mechanism of the combination-vibration phenomenon of fluid-structure of the plural circular structures. Two circular cylinders with the same diameter having a fundamental structure configuration are adopted. At first, the time-averaged fluid forces, the fluctuating fluid forces and vortex shedding frequency of two circular cylinders arranged in various positions are examined in detail. Next, the suppression of the fluid forces and vortex shedding of two circular cylinders is done by the passive control of flow. The passive control is established by two methods. Namely, one is the control of the approaching flow using a small flat plate; other is the control of the boundary layer on the surface using two tripping rods attached to the cylinders. The main results can be summarized as follows
(1) The characteristics of the time-averaged fluid forces, fluctuating fluid forces and vortex shedding of two circular cylinde
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rs arranged in various positions are elucidated. In particular, the fluctuating fluid forces, which are generated flow induced vibrations, are related with the form of arrangement of two circular cylinders.
(2) The suppression of the fluid forces acting on two circular cylinders in tandem arrangement is done by introducing a fine plate in the upstream of cylinders. As a result, the fluctuating fluid forces and vortex shedding of two circular cylinders, which are generated flow-induced vibrations, are substantially suppressed using a flat plate with a width of one tenth of the cylinder diameter.
(3) The suppression of the fluid forces acting on two circular cylinders in side-by-side arrangement is done by two tripping rods attached the surface of those. As a result, the fluctuating fluid forces and vortex shedding of two circular cylinders, which are generated flow-induced vibrations, are substantially suppressed.
(4) Flow induced-vibration of two circular cylinders can be sufficiently suppressed by use of the control methods established the present study. Also, the accumulation of the results of the present study can be sufficiently contributed for numerical analysis of the combination vibration of fluid-structure. Less
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