Quasi-steady monopole and tripole attractors for relaxing vortices
Quasi-steady monopole and tripole attractors for relaxing vortices
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用于松弛涡流的准稳态单极子和三极子吸引子
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
A. Bernoff
中科院分区：
文献类型：
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作者：
L. Rossi;J. Lingevitch;A. Bernoff
利用大雷诺数(Re)下二维N-S方程的完全非线性模拟，我们给出了一个阈值振幅，超过这个阈值，扰动的高斯单极子将弛豫为准稳定的旋转三极子，低于这个阈值，将弛豫为轴对称的单极子。由此得到的准稳态结构对小扰动是健壮的。我们提出了一种测量扰动衰减率到渐近涡度结构的方法，其中流线和恒定涡度的线条在某个旋转或平移的坐标系中对应。这些实验支持这样的假设，即与渐近结构的微小或中等偏差通过无粘性和粘性混合而衰减。
Using fully nonlinear simulations of the two-dimensional Navier–Stokes equations at large Reynolds number (Re), we bracket a threshold amplitude above which a perturbed Gaussian monopole will relax to a quasi-steady, rotating tripole, and below which will relax to an axisymmetric monopole. The resulting quasi-steady structures are robust to small perturbations. We propose a means of measuring the decay rate of disturbances to asymptotic vortical structures wherein streamlines and lines of constant vorticity correspond in some rotating or translating frame. These experiments support the hypothesis that small or moderate deviations from asymptotic structures decay through inviscid and viscous mixing.