Theree-dimensional dynamical structure of turbulence vortices Visualization and dynamics

采用数值模拟和可视化分析的方法研究了中性流体和导电流体中相干涡旋的结构和动力学特性。我们发现了以下有趣的结果。[1]精确地估计了湍流中物质线和表面的拉伸率，并确定了拉伸最强烈的地方。[2]本文将低压涡分析方法应用于各向同性湍流。各种物理特性的雷诺数依赖性，如横截面的大小，循环，管状旋流涡的体积，以及空间分布表明，集中涡发挥了动态的重要作用，即使在较大的雷诺数。提出了一种管涡的自动跟踪方法，可以方便地分析各涡的寿命。[3]通过对运动方程的可视化和逐项分析，阐明了绝对涡度为零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场中，观察到一个典型的动力学循环（热涡旋的产生和增长，磁场的增强，涡旋的破裂和磁场的减小）。

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.