A Study in Tornado-Like Vortex Dynamics
A Study in Tornado-Like Vortex Dynamics
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类龙卷风涡动力学研究
DOI：
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发表时间：
1979
期刊：
影响因子：
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通讯作者：
R. Rotunno
中科院分区：
文献类型：
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作者：
R. Rotunno
讨论了采用轴对称数值模型计算ward型涡室内流动的精细分辨率。特别注意旋涡-地面相互作用。随着旋流比S从0到1的变化，“角”区域（即r = z = 0附近）的涡结构发生了根本性的变化。对于S Lt；1、在上腔形成集中涡，而在角落不形成集中涡。在中等S下，我们观察到旋涡击穿，大振幅惯性波和非常强烈的旋涡运动在角落。当S = 1时，中心下沉气流向下地表渗透，边界层内发生涡旋击穿。这些结果与实验观察一致，并提出了对龙卷风的一些观测方面的解释。
Abstract Fine-resolution calculations using an axisymmetric numerical model of the flow within a Ward-type vortex chamber are discussed. Particular attention is paid to the vortex-ground interaction. Variations in the swirl ratio S from zero to unity lead to radically different vortex structure in the “corner” region (i.e., near r = z = 0). For S Lt; 1, a concentrated vortex forms in the upper chamber but not in the corner. At moderate S, we observe vortex breakdown, large-amplitude inertial waves, and very intense swirling motion in the corner. When S = 1, the central downdraft penetrates to the lower surface and the vortex breakdown occurs within the boundary layer. These results are consistent with experimental observations and suggest the explanation of a number of observed facets of tornadoes.