2000 Fiscal Year Final Research Report Summary
Development of 2-Phase CFD Models for Marine Environmental Issues
| Project/Area Number |
10305074
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| Research Category |
Grant-in-Aid for Scientific Research (A).
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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 | The University of Tokyo |
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Principal Investigator |
MIYATA Hideaki Univ.Tokyo, Environmental and Ocean Eng., Prof., 大学院・工学系研究科, 教授 (70111474)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Hideyuki Univ.Tokyo, Environmental and Ocean Eng., Assoc.Prof., 大学院・工学系研究科, 助教授 (00196859)
FUJINO Masataka Univ.Tokyo, Environmental and Ocean Eng., Prof., 大学院・工学系研究科, 教授 (10010787)
SATO Toru Univ.Tokyo, Environmental and Ocean Eng., Assoc.Prof., 大学院・工学系研究科, 助教授 (30282677)
PARK Jong-chun Univ.Tokyo, Environmental and Ocean Eng., Assistant, 大学院・工学系研究科, 助手 (80323541)
BABA Nobuhiro Osaka Prefecture Univ., Marine System Eng., Assoc.Prof., 工学部, 助教授 (10198947)
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| Project Period (FY) |
1998 – 2000
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| Keywords | CFD / two-phase flow / mass transfer / marine environments / greenhouse gas effect / bubble flow / droplet |
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| Research Abstract |
We often face two/multi-phase problems in marine environmental issues, such as the ocean sequestration of carbon dioxide, which is regarded as one of feasible and economical choices to reduce carbon dioxide in the atmosphere. Here the problem is the biological impact of CO2-rich seawater. Therefore, it is very important to simulate the dilution process of carbon dioxide in the deep ocean numerically. When one considers marine environmental issues from a viewpoint of fluid dynamics, he/she finds that there are several special scales in these problems. We picked up two rather small scales in this research project. One is the droplet scale (0.001-0.1m), and the other is the very local ocean scale (100-1000m).
For the droplet scale, there are two kinds of numerical methods to solve flows with interfaces : i.e. the front-capturing and front-tracking methods. We have developed two new numerical simulation codes in this scale, each of which corresponds to each of the methods, respectively. The
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front-capturing type utilizes the marker density concept to express the position and shape of the interface and solved the relationship between oscillatory deformation of a rising droplet and vertex shedding from it. In the front-tracking type, we adopt moving unstructured mesh systems and newly developed very thin layer method to solve high Schmidt number problems about a droplet. By this method, numerically empirical equations can be generated for the dissolution from a rising and deforming droplet. This equation can be used in the following larger-scale simulations as a sub-class model.
In the very local ocean scale, droplets are not treated individually but as volume fraction and number density. Therefore, this type of simulations manages to elucidate the behavior of droplet plume near the injection point in the deep ocean. Moreover, the chemical process of dissolution of carbon dioxide into seawater and its biological impact to individual organism are simultaneously solved. The results said that the pH experience each organism suffers hardly causes mortality for the amount of CO2 and injection period we set reasonably in the simulations. We also did plume-behavior experiments in room size and compared well the results with those of numerical simulations. Less
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