2007 Fiscal Year Final Research Report Summary
Velocity and temperature boundary layets in thermal turbulence and mean wind.
| Project/Area Number |
18560162
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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 | Nagoya University |
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Principal Investigator |
TSUJI Yoshiyuki Nagoya University, Graduate school ofengineering, Associate professor (00252255)
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| Project Period (FY) |
2006 – 2007
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| Keywords | thermal turbulence / mean wind / scaling / thermal / velocity boundary laver / low Pr |
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| Research Abstract |
Temperature and velocity fluctuations are measured simultaneously in thermal turbulence in a confined cell Temperature is measured by small thermister and velocity is measured by ultrasonic velocity profile monitor(UVP)and particle image velocimetory (PIV), respectively.Aspect ration is changed as 1.0, 2.0, 0.5.
It was found that the mean wind was identified as the long-time average flow pattern, not an instantaneously observed. It is drove by thermal plumes generated close to the wall. But the pattern of plume oscillation strongly depends on the aspect ratio. Using the water and mercury as the working fluid, the Pr number dependence of plume characteristics are studied.
Instantaneous flow pattern in water was investigated by PIV. The flow pattern is naturally tithe dimensional. it appears to be two-dimensional only when the long-time average is performed. Three dimensional Stir is depending on the plume oscillation, which is too complicated to clarify its statistics. Thermal and velocity boundary layers are affected by the mean wind. We continue to study this problem in the future.
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