Simulation of the Flow Past an Impulsively Started Cylinder Using a Discrete Vortex Method
Simulation of the Flow Past an Impulsively Started Cylinder Using a Discrete Vortex Method
复制标题
使用离散涡流法模拟经过脉冲启动气缸的流动
DOI：
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
F. Pépin
中科院分区：
文献类型：
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作者：
F. Pépin
翻译后摘要：涡方法是一种强大的方法，用于模拟不可压缩流在高雷诺数。这项工作扩展的基本方法，包括粘性的固体边界的存在下的影响。本文采用全粘性涡方法和快速并行算法相结合的方法，对冲击起动圆柱绕流进行了数值模拟。实验表明，这种流动的特征是主再循环区域内存在二次涡流。数值模拟成功地再现了这些二级结构在很宽的雷诺数范围内（Re=550至9500）。据观察，二次现象可以导致一个主要的流动重组，大大改变了运输的涡。当Re=550时，涡面平滑地卷起进入主涡。然而，对于Re=3000和9500，二次涡干扰该过程，并且涡量通量被重定向到圆柱体，在那里它积累成新的涡结构。脉冲起动后，阻力系数出现1/（t的平方根）奇异性。数值模拟捕捉到了这种行为，计算出的短时间阻力历史与匹配渐近分析预测的结果非常一致。
Abstract : Vortex methods are a powerful method for simulating incompressible flows at high Reynolds number. This work extends the basic method to include viscous effects in the presence of solid boundaries. The combination of a fully viscous vortex method with a fast parallel algorithm is used to simulate the flow past an impulsively started cylinder. Experiments have shown that this flow is characterized by the presence of secondary eddies within the main recirculating region. The numerical simulations successfully reproduced these secondary structures over a wide range of Reynolds number (Re=550 to 9500). It was observed that the secondary phenomenon can lead to a major flow reorganization by drastically altering the transport of vorticity. At Re=550, the vortex sheet smoothly rolls up into the primary vortex. For Re=3000 and 9500, however, secondary eddies interfere with that process and the flux of vorticity is redirected toward the cylinder where it accumulates into a new vortical structure. The impulsive start is followed by a 1/(square root of t) singularity in the drag coefficients. The numerical simulations captured this behavior and the computed drag history for short times is in close agreement with the one predicted by a matched asymptotics analysis.