| Project/Area Number |
11555144
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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 | 展開研究 |
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| Research Field |
Civil and environmental engineering
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| Research Institution | Ehime University |
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Principal Investigator |
WATANABE Masahiro Ehime Univ. Faculty of Engineering Assoc.Prof., 工学部, 助教授 (70036458)
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| Co-Investigator(Kenkyū-buntansha) |
KANKI Kazuo Kobe Univ. Faculty of Engineering Instructor, 工学部, 助手 (70031135)
KANDA Tohru Kobe Univ. Faculty of Engineering Prof., 工学部, 教授 (30029144)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥7,300,000 (Direct Cost: ¥7,300,000)
Fiscal Year 2000: ¥4,800,000 (Direct Cost: ¥4,800,000)
Fiscal Year 1999: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | air pressure / a mass of air / blowing of manhole covers / surface flooding / surcharged flow / storm water / drainage sewer system / urban runoff / 強雨時 |
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| Research Abstract |
In urban storm sewer pipe systems, manhole covers have been often blown away by a high pressure of compressed air in manholes, which is caused by a flow transition from open-channel to pressurized flow due to flow regulations (e.g., a gate closure at a pumping station in the downstream end of the pipe systems) during a heavy rain. In order to examine the efficiency of counter-measures to mitigate the occurrence of such a blowing phenomenon, a runoff simulation model of surcharged flow with masses of air in sewer pipe systems must be developed.
First, a storm water runoff simulation model of surcharged flow with masses of air at manholes in urban sewer pipe systems is proposed. In this model, the compressibility of the air is considered. Second, the model is applied to runoff experiments in a hydraulic model of storm sewer pipes with manholes, and the air-pressure hydrographs simulated by the simulation model are compared to the observed ones. As a restult, it is demonstrated that the simulation model proposed here can simulate very well the temporal variations of air-pressure in manholes. Third, the mechanism of blowing of a manhole cover is investigated through runoff experiments in the hydraulic model. As a result, the following are made clear : (1) air holes on a manhole cover have a definite effect of reducing the air-pressure in the manhole ; (2) lateral pipes (also called air ducts) attached to the wall of a manhole have a high efficiency to reduce the air-pressure in the manhole ; and (3) before a manhole cover is blown away by the collision with runoff water discharging out of the manhole, the manhole cover returns to their normal position after almost all the air in the manhole is exhausted.
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