Theree-dimensional dynamical structure of turbulence vortices Visualization and dynamics

湍流涡旋三维动力学结构可视化与动力学

• 批准号: 11837022
• 负责人: KIDA Shigeo
• 金额: $ 2.18万
• 依托单位: National Institute for Fusion Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11837022/
• 关键词: Turbulence; Coherent Vortex; Low-Pressure Vortex; Material Line; Material Surface; Rotational Shear Flow; Convection Vortex; Dipole Magnetic Field; 浮遊線; 乱流拡散; 熱対流渦; らせん渦層; ダイナモ; 可視化; 管状渦; 旋回流; 二重らせん構造; 渦の反平行接近; 渦のつなぎ替え

The structure and dynamics of coherent vortices in neutral and electrically conducting fluids are investigated by numerical simulation and visual analysis. We have found the following interesting results. [1] The stretching rates of material lines and surfaces in turbulence have been estimated accurately, and the place where the stretching is taking place most strongly is identified. [2] The method of low-pressure vortex analysis is applied to an isotropic turbulence. The Reynolds number dependence of various physical characteristics such as the size of cross-section, circulation, volume of tubular swirling vortices, as well as the spatial distribution suggests that concentrated vortices play a dynamically important role even at larger Reynolds numbers. An automatic tracking scheme of tubular vortices is developed, with which the life of each vortex can be analyzed more easily. [3] The life cycle (formation, development and breakdown) of straight coherent tubular vortices in a rotating shear turbulence of vanishing absolute vorticity is clarified by visualization and term-by-term analysis of the equations of motion. [4] In an axial magnetic dipole fields driven by thermal motion in a rotating spherical shell a typical dynamical cycle (generation and growth of thermal vortices, intensification of magnetic field, breakdown of vortices followed by diminution of magnetic field) is observed.

通过数值模拟和可视化分析研究了中性和导电流体中相干涡旋的结构和动力学。我们发现了以下有趣的结果。 [1] 已准确估计了湍流中材料线和表面的拉伸速率，并识别了拉伸发生最强烈的位置。 [2] 低压涡分析方法应用于各向同性湍流。各种物理特性（例如横截面大小、环流、管状旋转涡流的体积以及空间分布）的雷诺数依赖性表明，即使在较大的雷诺数下，集中涡流也发挥着重要的动态作用。开发了管状涡流的自动跟踪方案，可以更容易地分析每个涡流的寿命。 [3] 通过运动方程的可视化和逐项分析，阐明了绝对涡度消失的旋转剪切湍流中直相干管状涡的生命周期（形成、发展和破裂）。 [4] 在旋转球壳中由热运动驱动的轴向磁偶极子场中，观察到典型的动态循环（热涡旋的产生和增长、磁场的增强、涡旋的破裂，随后磁场的减小）。

项目成果

柳瀬眞一郎: "回転一様剪断乱流中の基本渦構造"京都大学数理解析研究所講究録. (印刷中).

Shinichiro Yanase：“旋转均匀剪切湍流中的基本涡流结构”京都大学数学科学研究所 Kokyuroku（正在出版）。

S. Goto and S. Kida: "Nonuniform stretched weight In line statistics turbulence"Proc. Turbulence and shear flow phenomena. 2. 263-268 (2001)

S. Goto 和 S. Kida：“非均匀拉伸重量在线统计湍流”Proc。

田中満: "回転剪断乱流の絶対過度ゼロ状態"京都大学数理解析研究所講究録. 1121. 157-164 (2000)

田中满：“旋转剪切湍流的绝对零瞬态”京都大学数学科学研究所Kokyuroku。1121.157-164（2000）。

C.Das: "Overall Self-Similar Decay of Two-Dimensional Turbulence"J.Phys.Soc.Japan. 70. 966-976 (2001)

C.Das：“二维湍流的整体自相似衰变”J.Phys.Soc.Japan。

H.Miura: "Identification and analysis of vortex structures in a weakly compressible isotropic turbulence"Proc.1st Intern.Symp.on Advanced Fluid Information. 641-646 (2001)

H.Miura：“弱可压缩各向同性湍流中涡旋结构的识别和分析”Proc.1st Intern.Symp.on Advanced Fluid Information。