| Project/Area Number |
13650974
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
海洋工学
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| Research Institution | OSAKA PREFECTURE UNIVERSITY |
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Principal Investigator |
BABA Nobuhiro OSAKA PREFECTURE UNIVERSITY, COLLEGE OF ENGINEERING, Assistant professor, 大学院・工学研究科, 助教授 (10198947)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Minoru DEPARTMENT OF INVESTIGATION JAPAN WEATHER ASSOCIATION, researcher, 調査部・研究員
KITAURA Ken-ichi OSAKA PREFECTURE UNIVERSITY, COLLEGE OF ENGINEERING, Lecturer, 大学院・工学研究科, 講師 (00081399)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2002: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2001: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | OCEAN MIXING / WEATHER / PYCNOCLINE / VERTICAL CIRCULATION / SURFACE COOLING / NAVIER-STOKES EQUATION / CLOSED SEA / WIND STRESS / ロール / キャビティ流 |
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| Research Abstract |
We investigate the mixing process in the surface layer of the ocean caused by the weather change by the experiment and the computation to elucidate its effect on the water quality in the closed sea.
First, we choose the two-dimensional cavity flow to reproduce the mixing process when the uniform wind continues to blow over the stably stratified fluid in the ocean surface. The results show that a primary circulation forms in the top downstream corner, growing gradually, but bounded by a stratified fluid beneath as it were a wall. It is found that the density interface formed by erosion of the basic density gradient is distorted by the primary circulation. This is one of the important mechanisms for the mixing of the fluid in the lower layer beneath.
Next, we simulate the mixing process in the upper ocean by cooling the surface by the atmosphere by the computation and experiment, and we examine the effects of the temperature variation on the process. The results show that the vertical profile of the horizontally averaged density distinguishes the mixed layer developing from the lower layer of stratification. When the cooling starts, the three-dimensional and regular cell structure is formed in the thin layer adjacent to the cooling top surface. The cool and dense fluid converges into the cell wall and falls down along it. It is found that the flow pattern of the three-dimensional vertical convection is dependent on the Reynolds number and it may affect the rate of mixing by surface cooling.
We have established the comer stone of the study on this theme because our understanding of the dominant feature of this process of the mixing in the upper ocean is good enough to predict the effects on the process of the weather conditions such as radiation, temperature, and wind stress although they are limited to the simple conditions.
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