| Project/Area Number |
17560521
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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 |
Building structures/materials
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| Research Institution | Tokyo Polytechnic University |
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Principal Investigator |
CAO Shuyang Tokyo Polytechnic University, Faculty of Engineering, Department of Architecture, COE Associate professor, 工学研究科, COE助教授 (00334532)
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| Co-Investigator(Kenkyū-buntansha) |
OZONO Shigehira Tokyo Polytechnic University, Faculty of Engineering, Department of applied physics, Professor, 工学部, 教授 (10169302)
YOSHIDA Akihito Tokyo Polytechnic University, Faculty of Engineering, Department of Architecture, Lecturer, 工学部, 講師 (90329219)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2006: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2005: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | circular cylinder / rectangular cylinder / wind direction / sudden velocity change / velocity shear / 辺長比 / 空気力 / Transient Flow / アクティブ制御 |
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| Research Abstract |
Strong wind that causes severe damages on structures is usually the transient wind, for instance, the tornado and downburst. These transient winds are difficult to be modeled in a wind tunnel because they not conventional boundary layer type flow. Therefore, characteristics of the wind load on structures in transient flow are not well understood yet.
In this study, we tried to look at the effects of two kinds of features of the transient flow on the aerodynamics of a bluff body, which is a typical section of a structure. The first feature is the sudden wind speed which occurs in tornado or downburst ; the second feature is the strong velocity shear in downburst flow. It is necessary to note here that the simulated flow just has some features of the transient flow, it has not similar structure as the natural transient wind.
Step-like velocity change was modeled in an actively controlled wind tunnel with a maximum acceleration of 50m/s2, in which the aerodynamic forces on a circular cylinder and a rectangular cylinder were investigated. The results showed that the overshoot of the drag and lift force do not take place if the acceleration is less than 50m/s2.
Strong shear flow was modeled also in the actively controlled wind tunnel with the maximum shear parameter of 0.27. The results show that the drag of a circular cylinder decrease with the increase of shear parameter, however the lift force increase with shear parameter, and the lift force acts from the high speed side to low speed side. The ground effect that acts on the real structures was not considered in this study.
Continuous study will be carried out on three-dimensional building models.
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