The influence of turbulence on a columnar vortex
The influence of turbulence on a columnar vortex
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DOI：
10.1063/1.1858532
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发表时间：
2005-02
影响因子：
4.6
通讯作者：
N. Takahashi;H. Ishii;T. Miyazaki
中科院分区：
文献类型：
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作者：
N. Takahashi;H. Ishii;T. Miyazaki
对柱状涡与外部湍流的相互作用进行了数值研究。Lamb-Osee涡被浸没在初始各向同性的均匀湍流场中，其本身是通过对衰减湍流的直接数值模拟而产生的。通过对流场的可视化，详细研究了柱状涡周围非均匀细湍涡的形成和涡核变形。最初随机的湍流涡旋(蠕虫)缠绕在柱状涡周围，变成螺旋形。对两点能谱和两点能化谱等统计量进行了计算，并与快速扭曲理论的理论预测进行了比较。涡面附近的轴向速度关联占主导地位，而蜗杆包裹处的径向速度关联较大。在柱状涡与外部湍流相比较强的情况下，外部速度扰动被柱状涡所阻挡，从而使柱状涡与外部湍流相互作用。
The interaction between a columnar vortex and external turbulence is investigated numerically. A Lamb–Oseen vortex is immersed in an initially isotropic homogeneous turbulence field, which itself is produced numerically by a direct numerical simulation of decaying turbulence. The formation of inhomogeneous fine turbulent eddies around the columnar vortex and the vortex-core deformations are studied in detail by visualizing the flow field. The initially random turbulent eddies (worms) are wrapped around the columnar vortex and become spirals. Statistical quantities, such as two-point-energy spectra and two-point-enstrophy spectra, are evaluated and compared with the theoretical predictions from rapid distortion theory. The axial velocity correlation dominates near the vortex surface, whereas the radial velocity correlation becomes larger where the worms are wrapped. Where the columnar vortex is strong compared with the external turbulence, external velocity disturbances are blocked by the vortex and they c...