| Project/Area Number |
62850097
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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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 |
TSUCHIYA Yoshito Professor, Disaster Prevention Research Institute, Kyoto University, 防災研究所, 教授 (90025883)
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| Co-Investigator(Kenkyū-buntansha) |
磯部 憲雄 海上電機, 第一技術部, 部員
森田 行司 海上電機, 第一技術部, 部長
西村 達郎 日本気象協会, 調査部海洋調査課, 主事
TANAHASHI Teruhiko Director, Observation Division, Japan Meteorological Agency, 調査部, 部長
YOSHIOKA Hiroshi Instructor, Disaster Prevention Research Institute, Kyoto University, 防災研究所, 助手 (10027287)
NISHIMURA Tatsuro Head, Observation Division, Japan Meteorological Agency
MORITA Koji Director, First Technical Division, Kaijo-Denki
ISOBE Norio First Technical Division, Kaijo-Denki
仲井 圭二 日本気象協会, 調査部, 主事
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥13,400,000 (Direct Cost: ¥13,400,000)
Fiscal Year 1988: ¥5,400,000 (Direct Cost: ¥5,400,000)
Fiscal Year 1987: ¥8,000,000 (Direct Cost: ¥8,000,000)
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| Keywords | Ultra-sonic current meter / Surf zone / Nearshore current / Longshore current / 流れの構造 |
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| Research Abstract |
1. Decelopment of ultra-sonic-type current meter for long term observation of currents in surf zone: Based on ultra-sonic current meters available in surf zones were developed and improved. for noise disturbance by bubble intrusion and drifting sand by wave breaking in surf zones, a noise disposing circuit of the current meter was newly developed. The currents in the surf zone are three dimensional due to incoming waves and their induced nearshore currents. The current meter probe was also improved being able to measure three dimensional components of the currents. Long term observations of about two years were carried out for examining the applicability of the newly developed current meters and investigating currents in the surf zone at ogata coast.
2. Characteristics of the currents in surf zones: A lot of field data of the currents at ogata coast were collected by use of the current meter. The pbserved data were analysed partly to investigate characteristics of long term nearshore currents. 1) No remarkable influence of tides exists and remarkable ones exist due to winds and waves. In winter period, styong currents exist five times a month and in summar period weak currents exist, but their duration are usually very short. 2) When a mosoon passes, at the earier stage of wind waves longshore currents exist remarkablly, but in the fully developed sea state strong offshore currents exist and their maximum velocities reach several tens cm/s. This findings of the nearshore currents may contribute greatly to solve the beach processes.
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