Near-Surface Vortex Intensification through Corner Flow Collapse
Near-Surface Vortex Intensification through Corner Flow Collapse
复制标题
通过角流塌陷增强近地表涡旋
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
W. S. Lewellen
中科院分区：
文献类型：
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作者：
D. Lewellen;W. S. Lewellen
摘要结果来自一类非定常涡旋演化的大涡模拟，这种涡旋演化有时可能在龙卷风发生或龙卷风变异中发挥作用。从一个高旋流母涡开始，通过表面/拐角/核心区域有过量的低旋流，大半径处低旋流近表面入流的扰动可能引发随后的动态“拐角流崩溃”，相对于速度尺度上一个数量级或更多的高处条件，产生戏剧性的近表面强化。本文提出了一个更详细的处理的物理和模拟的角落流崩溃，扩大后，在一个配套文件中给出的介绍，处理近表面涡强化更普遍的稳定和非定常条件。的发病，加剧，结构和持续时间的现象的基本缩放探索作为一个功能的一些主要的物理参数。无量纲的变化率...
Abstract Results are presented from a large set of large-eddy simulations of a class of unsteady vortex evolution that may sometimes play a role in tornadogenesis or tornado variability. Beginning with a high-swirl parent vortex with an excess of low-swirl flow through the surface/corner/core region, perturbation of the low-swirl near-surface inflow at a large radius can trigger a subsequent dynamic “corner flow collapse” producing dramatic near-surface intensification relative to conditions aloft of an order of magnitude or more in velocity scale. This paper presents a more detailed treatment of the physics and simulation of corner flow collapse, expanding upon the presentation given in a companion paper treating near-surface vortex intensification more generally for both steady and unsteady conditions. The basic scaling of the onset, intensification, structure, and duration of the phenomenon is explored as a function of some of the dominant physical parameters involved. A dimensionless rate of change of...