The dynamics of a viscous vortex dipole
The dynamics of a viscous vortex dipole
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粘性涡旋偶极子的动力学
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
M. Rossi
中科院分区：
文献类型：
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作者：
I. Delbende;M. Rossi
通过数值模拟和理论分析，对二维粘性偶极子的结构进行了精确分析。首先，提出了一种模型，该模型基于涡斑和具有分布式涡度轮廓的涡旋之间的启发式关系来计算偶极子速度和涡旋椭圆率。其次，在涡旋彼此接近的阶段，假设广义自相似解来描述偶极子粘性扩散过程中观察到的涡度分布。给出了数值和理论考虑，证明了这种假设的充分性。最后，以分析形式给出了偶极子后面产生的尾部结构，这与数值结果相比是有利的。
The structure of a two-dimensional viscous dipole is accurately analyzed using both numerical simulations and theoretical analyses. First, a model is proposed, which computes the dipole velocity and the vortex ellipticity based on a heuristic relation between a vortex patch and a vortex with distributed vorticity profile. Second, during the stage where vortices are close to each other, a generalized self-similar solution is postulated to describe the vorticity profiles observed during the viscous spreading of the dipole. Numerical as well as theoretical considerations are given, which demonstrate the adequacy of such a hypothesis. Finally the structure of the tail that is generated behind the dipole is given in an analytical form, which favorably compares to numerical results.