2006 Fiscal Year Final Research Report Summary
Effect of Turbulence Parameter on Heat and Particle Diffusion in a Atmospheric Turbulenc
| Project/Area Number |
17560145
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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 |
Fluid engineering
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| Research Institution | Toyohashi University of Technology |
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Principal Investigator |
MAKITA Hideharu Toyohashi Univ. of Tech., Department of Engineering, Professor, 工学部, 教授 (40135413)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Fluid Engineering / Atmospheric Turbulence / Hear and Mass Transfer / Turbulent Diffusion / Meandering Motion / Wind Tunnel Experiments / Thermo Anemometer / Flow Visualization |
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| Research Abstract |
The present research aimed to examine the effect of turbulence parameter on heat and particle diffusion in a large-scale turbulence, R_λ=400 (Re_M =10^6〜10^7), generated by a turbulent shear flow generator. Its velocity and temperature fields were measured by a thermo-anemometer and a I-type cold-and X-type hot-wire probe. The streamwise evolution of thermal plume was obtained through statistical analysis on velocity and temperature fluctuations.
(1) The meandering motion of thermal plume was observed in a wind tunnel. The variation of probability density function of mean temperature gave good agreement with the Taylor's diffusion theorem and short time diffusion process was realized.
(2) The meandering motion was affected by the large-scale turbulent eddy. When the streamwise interval of thermal plume, LI, was almost same as the longitudinal integral scale, LI didn't change in the stremwise distance. When the spanwise length of the thermal plume equaled the lateral integral scale, its diffusion shifted to long time diffusion process.
(3) Compared with thermal diffusion in a grid turbulence field, heat flux was extremely large and spanwise thermal transportation was very active in the large-scale turbulence. As a result, the diffusion coefficient was K=180cm2/s for Rλ=430.
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Research Products
(12 results)
