A MODEL FOR THE FORMATION OF OBLIQUE SHEDDING AND CHEVRON PATTERNS IN CYLINDER WAKES
A MODEL FOR THE FORMATION OF OBLIQUE SHEDDING AND CHEVRON PATTERNS IN CYLINDER WAKES
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DOI：
10.1063/1.858292
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发表时间：
1992-04-01
期刊：
影响因子：
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通讯作者：
MONKEWITZ, PA
中科院分区：
文献类型：
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作者：
ALBAREDE, P;MONKEWITZ, PA
它表明，涉及从二维海崖体，特别是圆柱体的斜涡脱落的流动可视化的许多功能，定性良好地描述了一维模型，它表示沿沿着平行于圆柱体的线布置的扩散耦合振荡器。 在数学上，理想化的模型由横向金-朗道方程组成，其中的系数由实验确定。 在物理术语中，该模型描述了示踪剂颗粒图案的形成（例如，烟），随后正好对流到下游。 它示出，在模型中，在冲动启动实验，“涡脱落”开始平行于气缸。 倾斜脱落区域从圆柱体端部开始发展，并导致对称端部条件下的稳态人字形。 作为雷诺数的函数的脱落角的选择规则来自模型和实验相比。
It is demonstrated that many features of flow visualizations involving oblique vortex shedding from two-dimensional bluff bodies, cylinders in particular, are qualitatively well described by a one-dimensional model, which represents diffusively coupled oscillators arranged along a line parallel to the cylinder. In mathematical terms, the idealized model consists of a transverse Ginzburg-Landau equation, in which the coefficients are determined experimentally. In physical terms, the model describes the formation of a pattern of tracer particles (e.g., smoke) over a very short streamwise interval which is subsequently just convected downstream. It is shown that in the model, as in impulsively started experiments, "vortex shedding" starts parallel to the cylinder. Regions of oblique shedding then develop from the cylinder ends and lead to steady-state chevrons for symmetric end conditions. Selection rules for the shedding angle as a function of Reynolds number are derived from the model and compared to experiments.