| Project/Area Number |
61850081
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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 |
船舶抵抗・運動性能・計画
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| Research Institution | Yokohama National University |
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Principal Investigator |
TAKEZAWA Seiji Professor, Faculty of Engineering, Yokohama National University., 工学部, 教授 (10017874)
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| Co-Investigator(Kenkyū-buntansha) |
HIRAYAMA Tsugukiyo Associate Professor, Faculty of Engineering, Yokohama National University., 工学部, 助教授 (00018061)
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| Project Period (FY) |
1986 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥31,600,000 (Direct Cost: ¥31,600,000)
Fiscal Year 1988: ¥10,200,000 (Direct Cost: ¥10,200,000)
Fiscal Year 1987: ¥7,600,000 (Direct Cost: ¥7,600,000)
Fiscal Year 1986: ¥13,800,000 (Direct Cost: ¥13,800,000)
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| Keywords | Ocean wave / Directional Spectra of Waves / Measuring System of directional spectra / Analysis of directional spectra / 海洋波の方向分布関数 / 方向スペクトル計測用波高計群 / 方向スペクトル / 短波頂不規則水波 / 人工不規則水波の発生 / 方向スペクトルの計測 |
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| Research Abstract |
A developmental research on the practical measuring system of directional spectra of ocean waves was carried out by measurement of the artificial short crested irregular waves generated in the long experimental tank of Yokohama National University. Those short crested irregular waves were exactly given the specified directional spectra by the newly developed multi segmented wave generator.
Consequently a new complete system which has following specialties was developed.
1. A new wave probe for multi points using laser beams that projected vertically from underwater was invented. Laser spots on the wave surface are taken by a TV camera from diagonally upward direction and recorded by the video tape recorder. Recorded video is processed, read out by digital and converted to surface elevation of multi points by the digital calculation.
This new laser wave probe has great merits, viz. non contact measurement,highprecision,high frequency response,small size etc.
2. Analysis of directional spectra is Performed in short time by the personal computer system with high speed plotter printers. Directional spectra are calculated by the adaptation of the maximum likclihood method under the fine resolution of wave frequency and direction. Hard copies of various figures of the measured directional spectra can get in almost real time at that measuring place.
3. It is not so difficult to make a new measuring system for actual ocean by the development of this new system.
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