| Project/Area Number |
06660293
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Irrigation, drainage and rural engineering/Rural planning
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| Research Institution | Ibaraki University |
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Principal Investigator |
KINOSE Koichi Ibaraki Univ., Faculty of Agriculture, Assistant Professor, 農学部, 助教授 (80234326)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAISHI Katsuya Ibaraki Univ., Faculty of Agriculture, Assistant, 農学部, 助手 (40180236)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1995: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1994: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | accumulated sediment / Self-regulating gate / rapidly varied unstesdy flow / efficiency of the sediment flash / concentration of salt / river-mouth improvement / river mouth closing / 河口閉塞 |
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| Research Abstract |
[I]This flash-board is a kind of the gate system which consists of the gate board and the weight linked to the board by the wire. THe system dams up the flow and the discharged water flashes down the canal course automatically. The gate board overturns by the hydro-static pressure when the storage weter surface reaches to an established level. Therefor the system is not need any energy to drive it. This system is used for flashing down the polluted water and the accumulated sediment in the drainage canals or the small rivers.
In this research, the timing's of the overturn and the return of the gate board are predicted. The rapidly varied unsteady flow with the surge, which ocurs ofter the over-turn of the gate board, is analyzed using the numerical method based on 'MaCormack's scheme'. The numerical method is modified by the addition of second-order artifacial viscosity term to the original scheme. And the efficiency of the sediment flash of the flow is estimated from the results of the
… More
movable bed experiments.
[II]An effective method for river-mouth improvement is proposed on the basis of the results of the experiments.
Regarding this method, reinforcement of the tractive force and a disturbance of flow and sand movement has been applied. The former is induced by the self-regulating gate system which has been proposed in this research. The latter occurs due to the series bottom pile systems which are set up along the flow near the river-mouth. The gate system causes the river flow to dam up and the water discharged flashes down automatically. The rapidly varied unstesdy flow with the surge after the overturn of the gate board has a large tractive force. Reinforcement of the tractive force occus due to this flow. The series bottom pile system is mede up of several sheet piles arranged in a straight line with proper separations and angles. Two series's of pile system are set up on the right- and left- handsides of the main flow near the river-mouth. Each sheet pile of the series pile system is a arranged so as to converge water flow between the pile systems on the both side and to diverge sediment outside of that region. The sand transported from the main flow region accumulates behind the both pile systems. A remarkable water route can be formed by this reason.
The optimum arrangement of the piles is also discussed from the results of the movable bed experiments. Less
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