Vortex Core Dynamics in a Swirling Jet Near Vortex Breakdown
Vortex Core Dynamics in a Swirling Jet Near Vortex Breakdown
复制标题
涡流破裂附近旋流射流中的涡核动力学
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
J. O’Connor
中科院分区：
文献类型：
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作者：
Sean Clees;J. Lewalle;M. Frederick;J. O’Connor
在涡流射流中研究涡流核心的动力学，涡流数在涡流破裂的临界涡流数范围内。涡流破裂是旋转射流结构中的分叉，导致沿射流中心线建立停滞点和再循环区域。在这项研究中，我们探索了涡流破裂附近的旋转射流的动力学。对时间平均速度场和剖面的研究导致了三种流态的识别：预击穿、近击穿和击穿后。使用动态模式分解、朗肯涡拟合和适当的正交分解来进一步分析这些状态中的速度场，以表征射流动力学，特别关注涡破裂的再循环区域特征的发展。在击穿后状态中还识别了进动涡核，并讨论了其行为。
The dynamics of the vortex core are investigated in a swirling jet at swirl numbers in the range of the critical swirl number for vortex breakdown. Vortex breakdown, a bifurcation in the structure of a swirling jet, results in the establishment of a stagnation point and recirculation region along the centerline of the jet. In this study, we explore the dynamics of the swirling jet near vortex breakdown. Investigation of time-averaged velocity fields and profiles leads to the identification of three flow regimes: pre-breakdown, near-breakdown, and post-breakdown. Velocity fields in these regimes are further analyzed using dynamic mode decomposition, Rankine-vortex fitting, and proper orthogonal decomposition to characterize jet dynamics with a particular focus on the development of the recirculation region characteristic of vortex breakdown. A precessing vortex core is also identified in the post-breakdown regime and its behavior is discussed.