| Project/Area Number |
14340033
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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 |
General mathematics (including Probability theory/Statistical mathematics)
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| Research Institution | Nagoya University |
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Principal Investigator |
KANEDA Yukio Nagoya University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (10107691)
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| Co-Investigator(Kenkyū-buntansha) |
GOTOH Toshiyuki Nagoya Institute of Technology, Graduate School of Information Science, Professor, 大学院・工学研究科, 教授 (70162154)
ISHII Katsuya Nagoya University, Information Technology Center, Professor, 情報連携基盤センター, 教授 (60134441)
ISHIHARA Takashi Nagoya University, Graduate School of Engineering, Assistant Professor, 大学院・工学研究科, 講師 (10262495)
YOSHIDA Kyo University of Tsukuba, Graduate School of Pure and Applied Sciences, Research Associate, 大学院・数理物質科学研究科, 助手 (30335070)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥11,000,000 (Direct Cost: ¥11,000,000)
Fiscal Year 2004: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2003: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2002: ¥5,300,000 (Direct Cost: ¥5,300,000)
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| Keywords | Inhomogeneous Anisotropic Turbulence / Direct Numerical Simulation(DNS) / Universal Structure of Turbulence / Statistical Theory of Turbulence / Reynolds Number Dependence / Large Eddy Simulation / Plane Poiseuille Turbulence / Stratified Turbulence / 非一様非等方性乱流 / 乱流モデル / 非一様非等方乱流 / 大規模直接数値シミュレーション / ラグランジュ的スペクトル統計理論 / ラージ・エディ・シミュレーション / 乱流の普遍則 / 一様剪断乱流 / ポアズイユ乱流 |
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| Research Abstract |
The aim of this study is to understand the universal structure of turbulence, which is indispensable for developing statistical theory of inhomogeneous anisotropic turbulence. On the basis of the method of statistical theory of turbulence and large scale Direct Numerical Simulation(DNS), the study has clarified the followings :
(A)DNS of Turbulence and Data-Analysis :
By analyzing the data of the world largest DNS of turbulence with the number of grid points up to 4096^3, more than 10^11 degrees of freedom and 10^22 nonlinear interactions, we clarified some of (i)Reynolds(Re)-dependence of various statistics, and (ii)asymptotic universality in the high Re-limit. We also performed quantitative examination of (iii)Kolmogorov's similarity hypotheses, and (iv)the eddy-viscosity hypothesis in Large Eddy Simulation, at high Re.
(B)Universal Structure and Modeling of Anisotropic Turbulence :
We derived an expression for the anisotropic spectrum at small scales of homogeneous turbulent shear flow on the basis of the analysis of a Lagrangian spectral closure equation. We also derived a general expression for the anisotropic spectrum in stratified turbulence, confirmed its form by DNS, and showed the validity of an idea similar to that of the linear responses theory for non-equilibrium system.
(C)DNS of Wall Bounded Turbulence and Data-Analysis :
Plane Poiseuille turbulence is one of the most basic turbulences among boundary layer turbulences or turbulences with solid wall. In order to perform the DNS, we made codes based on the Chebyshev-tau method and a Combined Compact Scheme, respectively, and validated their performance. By the DNS, we clarified the dependence on the wall normal distance and Re of eddy-scale distribution, by analyzing the wall-normal velocity correlation spectrum.
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