2002 Fiscal Year Final Research Report Summary
Filed Observation in Urban Boundary Layer and a New Similarity Law
| Project/Area Number |
12450197
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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 | Tokyo Institute of Technology |
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Principal Investigator |
KANDA Manabu Graduate School of Science and Engineering, Associate Professor, 大学院・理工学研究科, 助教授 (90234161)
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| Co-Investigator(Kenkyū-buntansha) |
MORIWAKI Ryo Graduate School of Science and Engineering , Research Associate, 大学院・理工学研究科, 助手 (10302952)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Urban bouadary layer / Turbulent transfer / Scalar / Filed observation / Wavelet analysis / Similarity function |
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| Research Abstract |
A long-term flux measurement of momentum, heat, moisture and CO_2 has been conducted in densely-built up residential area in Tokyo. Consequently, new similarity functions of flux, deviation and dissipation related to turbulent flow have been proposed. Moreover, the detailed mechanism of turbulent exchange process over a complicated urban geometry has been investigated through wavelet analysis and the following results were obtained. (l) The turbulent characteristics showed a significant diurnal variation. Particularly in the morning, large scale turbulent organized structure extending to boundary layer height entrained the upper air, resulting in the similar transfer of momentum, heat, moisture and C0_2. (2) Turbulent organized structures generated by shear-instability and thermal instability make dominant role on turbulent transport. They transfer heat, moisture, and CO_2 in different efficiency. The turbulent transfer of heat is most effective. One of the reasons is that the surface-heterogeneity of temperature is smaller than those of moisture and CO_2, and another possibility is that heat is the active scalar of direct generation of thermal plumes.
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