1991 Fiscal Year Final Research Report Summary
A Study on Sediment Transport and River Bed Variation Based on the Simultaneous Measurements of Flow and Sediment Movement in Various Scales
| Project/Area Number |
02302066
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Hydraulic engineering
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
ASHIDA Kazuo Kyoto University, Disaster Prevention Research Institute, Professor, 防災研究所, 教授 (30027205)
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| Co-Investigator(Kenkyū-buntansha) |
HASEGAWA Kazuyoshi Hokkaido University, Faculty of Engineering, Research Associate, 工学部, 助手 (70001328)
SAWADA Toyoaki Kyoto University, Disaster Prevention Research Institute, Associate Professor, 防災研究所, 助教授 (60027258)
IKEDA Hiroshi University of Tsukuba, Institute of Geoscience, Associate Professor, 地球科学系, 助教授 (20015986)
SAWAI Kenji Kyoto University, Disaster Prevention Research Institute, Professor, 防災研究所, 助教授 (70109073)
NEZU Iehisa Kyoto University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (30109029)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Sediment Transport / River Bed Variation / Measurement / Flood Flow / Stream Variation / Field Observation / Turbulent Flow / Laboratory Automation |
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| Research Abstract |
In this study, the mechanism of sediment transport and river bed variation such as suspension of the sediment by eddies, bed configuration, sediment discharge and sediment sorting with various scales including laboratory flumes and field rivers are clarified through simultaneous measurements of flow and sediment movement with the help of various new techniques. This work had been promoted as the joint research with the Working Group of Hydraulics Committee of Japan Society of Civil Engineers. In December, 1991, a mini-symposium "simultaneous measurements of flow and sediment transport" was co-held by the both groups. The results obtained by each investigator are summarized as follows:
Nezu measured the turbulent structure of unsteady flow on dunes in a laboratory flume, using two component laser anemometer and water level gage, and found that the turbulence intensity and suspended sediment concentration are higher in the rising stage than in the descending stage of a flood.
Sawai devised
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a new technique to measure a bed form along arbitrary curves automatically using a personal computer and clarified the characteristics of the bed variation in a meandering channel during a flood, in which no remarkable variation of bed level was found.
Ikeda clarified the longitudinal sediment sorting in a large scale laboratory flume and discussed about the effect of rocky stream bed in River Ooi. He also emphasizes about the role of abrasion on the sediment size variation along river courses.
Sawada and Ashida clarified the characteristics of the sediment runoff in a mountain stream through long term observation in Ashiaraidani basin of Jinzu River. It was found that the variation of sediment discharge is highly correlated with stream variation. They also considered about what and how accurate to measure in future observation.
Hasegawa, Kinoshita, Nishida and Tominaga clarified the flood flow and sediment transport in low land rivers through observation in River Ishikari, River Shiribetsu, River Takase and Gumma Irrigation Channel etc. Through Tominaga's work, the similarity of flow structure between laboratory flumes and field rivers was ascertained. Nishida et. al devised a new technique to support the probes using a pair of ropes beside a bridge and observed the variation of salinity and velocity field near a river mouth. Hasegawa observed the flow velocity and suspended sediment simultaneously near the mouth of River Ishikari and found that the peak of shear velocity and sediment concentration appears before that of the water level. Kinoshita tried to utilize a hover craft and a flowing buoy to measure bed profile quickly and found out a series of bed forms with the wave length ratio about 6. Less
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