Visualization of instability processes in pure thermal plume
Visualization of instability processes in pure thermal plume
复制标题
纯热羽流不稳定过程的可视化
DOI：
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
E. Khrapunov
中科院分区：
文献类型：
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作者：
E. Kuznetsov;E. Kolesnik;E. Khrapunov
本文介绍了在加热水平圆盘上形成的自然对流的物理和数值模拟结果。本研究的主要目的是分析自由对流羽流的各种稳定状态随受热表面温度的变化情况。所提出的流型使我们有可能确定温度因子的临界值，在这个临界值处观察到稳定状态的变化。将物理建模框架下得到的可视化数据与数值计算得到的流型数据进行了比较和补充。提出了一种单独气团（“泡”）形成的机制，它既破坏了近壁层，也破坏了形成的向上流动。研究发现，出现的软分叉的特征是扰动幅度急剧增加，温度因子的值略有增加：羽流边界的初始波动导致热平衡的进一步破坏和羽流的形成。
In the paper, the results of physical and numerical simulation of a natural convective flow formed over a heated horizontal disk are presented. The main purpose of this study is to analyze the occurrence of various stable states of a free-convection plume depending on the temperature of the heated surface. The presented flow patterns make it possible to determine the critical value of the temperature factor at which a change of stable states is observed. The visualization data obtained in the framework of physical modeling are compared and supplemented with data on flow patterns obtained numerically. A mechanism for the formation of separate air masses (“puffs”), which destroy both the near-wall layer and the formed upward flow is proposed. It was found that the emerging soft bifurcation is characterized by a sharp increase in the amplitude of perturbations with a slight increase in the value of the temperature factor: initial fluctuations of the plume boundary lead to further disruption of the heat balance and formation of puffs.