2003 Fiscal Year Final Research Report Summary
Studies on Applying Spiral Flow Type Channel to Develop Spiliways
| Project/Area Number |
13460108
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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 | 一般 |
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| Research Field |
Irrigation, drainage and rural engineering/Rural planning
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| Research Institution | University of Miyazaki |
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Principal Investigator |
AKIYOSHI Yasuhiro University of Miyazaki, Faculty of Agriculture, Professor, 農学部, 教授 (30041031)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAZONO Tkefumi University of Miyazaki, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (80315358)
KOJIMA Haruhiko Meiji University, Faculty of Agriculture, Lecturer, 農学部, 講師 (10277725)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Spiral Flow / Spillway / Chute Flow / 流水制御 / 洪水吐 |
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| Research Abstract |
A pipeline is usually constructed in the areas of where the slope is greater than 1/5. However, constructing pipelines results in problems such as blockage by driftwood or sand inside the initial portion of the pipeline, overflow of currents, and collapse of the pipeline. It is then very. difficult to remove the blockage.
For these reasons, in this study an open channel structure was developed which can be constructed in areas with a 1/1 slope or when the curve angle of a channel is 90 degrees.
This method of flow control is a newly developed technology. By altering the rectangular channel into a circular wall channel, the upward flow energy of high speed currents can be transformed into spiral flow energy, making the currents flow smoothly.
It is possible to apply this technology of spiral flow type channel structure by constructing this system in mountains with steep slopes and curved channels or chutes. This method is practical in spillways located in narrow places, as well as in curved spillways of dams or reservoirs. At present, this new type spillway is in operation in one location.
When the weir width of spillways is the same as the width of the arc section channel, flows can be controlled easily; but when the weir width is equal to or greater than the width of the channel, it causes overflows. Therefore, from now on studies on improving the shape of spillway weir to zigzag weir to make its width equal the width of the channel are planned on being carried out.
Furthermore, it is worthy of special mention that this new spiral type channel structure can reduce the construction cost as much as 30-40%.
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