| Project/Area Number |
13450069
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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 |
Fluid engineering
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| Research Institution | Tohoku University |
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Principal Investigator |
HANAZAKI Hideshi Tohoku University, Institute of Fluid Science, Associate Proffesor, 流体科学研究所, 助教授 (60189579)
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| Co-Investigator(Kenkyū-buntansha) |
SHA Wei-ming Tohoku University, Department of Geophysics, Associate Professor, 大学院・理学研究科, 助教授 (60251716)
MIYAZAKI Takeshi University of Electrocommunications, Department of Mechanical and Control Engineering, Professor, 大学院・電気通信学研究科, 教授 (50142097)
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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 |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 2002: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2001: ¥5,400,000 (Direct Cost: ¥5,400,000)
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| Keywords | turbulence / stratification / rotation / inertial-gravity waves / flux oscillations / rapid distortion theory |
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| Research Abstract |
Solutions for the stratified rotating turbulence have been obtained by the RDT (rapid distortion theory) to investigate the effects of combined effects of stratification and rotation, including the counter-gradient heat flux and the vertical heat transfer. By looking for the exact analytical solutions in RDT's linear frame work, it has been clarified how the spectra of the kinetic energy and the heat affect the vertical heat flux, including the phenomenon of the counter-gradient heat flux. Particular attention has been paid to the fact that there are two time scales in stratified rotating turbulence and we have shown how the two time scales determined by the rotation and the buoyancy frequency affect the turbulence. The overall results agreed well with the DNS for low Froude number (strongly stratified) flows. For example, many of the characteristics of stratified rotating turbulence, e.g., the phase shift of the flux oscillations due to rotation, has been explained by this linear theory. For the passive scalar transfer in stratified turbulence, we have shown the importance of the initial conditions and the unsteadiness of turbulence which have been often overlooked in the previous study of passive scalar diffusions. The results of this study will be of help in future modeling of turbulent diffusion in the atmosphere and the ocean.
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