2005 Fiscal Year Final Research Report Summary
Investigation of the mechanism of the generation of rip current and development of the procedure for predicting rip current using remote sencing.
| Project/Area Number |
15360266
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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 |
水工水理学
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| Research Institution | Osaka University |
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Principal Investigator |
DEGUCHI Ichiro Osaka University, Graduate School of Engineering, Professor, 大学院工学研究科, 教授 (00029323)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEHARA Kousei Kinki University, Department of Science and Engineering, Associate Professor, 理工学部, 助教授 (50216933)
ARAKI Susumu Osaka University, Graduate School of Engineering, Associate Professor, 大学院工学研究科, 講師 (80324804)
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| Project Period (FY) |
2003 – 2005
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| Keywords | orographic rip current / gusty rip current / large cusp / rip channel / remote sensing / K-GPS / image data processing |
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| Research Abstract |
More than 100 lives were lost by accidents during swimming in the sea every year. It is reported that large part of the accidents were caused by the rip current. If we can predict the occurrence of rip current in advance, it is possible to reduce number of accident through the warning system. However, a certain kind of rip current suddenly. comes in to existence in a very narrow region and its lifetime is not so long. It is generally impossible to predict the occurrence of this kind of rip current. It is needless to say that this kind of rip current is extremely dangerous for swimmers.
At the same time, rip current becomes transporting agency of bed material in the very shallow water region towards offshore.
The aim of this study is to develop a rip current observation system by using local remote sensing from the balloon and to investigate the occurrence condition of rip currents. Surface displacement measuring system by stereo-camera images and bottom topography measuring system using K-GPS are also developed.
Almost all patterns of orographic rip currents reported until now can be recorded in the field observations. Some of the measured flow patterns are reproduced by the numerical simulations of wave fields and wave induced current on the measured bottom topography by K-GPS. Measuring systems of mesoscale bottom topography and wave field are also developed and verified through the field observations.
These results surely set up effective procedures for measuring wave fields and wave induced current in very shallow water regions.
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