Identifying turbulent structures through topological segmentation
Identifying turbulent structures through topological segmentation
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通过拓扑分割识别湍流结构
DOI：
10.2140/camcos.2016.11.37
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
R. Grout
中科院分区：
文献类型：
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作者：
P. Bremer;A. Gruber;Janine Bennett;A. Gyulassy;H. Kolla;Jacqueline H. Chen;R. Grout
提出了一种从湍流中提取涡旋结构的新方法，该方法利用指示函数标量场的拓扑分割来识别单个涡旋的影响区域。这解决了矢量场拓扑分析中的一个长期挑战：通常使用的指示函数基于局部速度矢量场产生标量场；重建特定结构的影响区域需要选择阈值来定义涡旋范围。在实践中，相同的阈值在整个给定流中很少有意义。通过考虑指示场函数的拓扑结构，可以分离涡旋强度和涡度的特征，减少阈值选择的模糊性。所提出的方法能够同时识别横流结构中观察到的几种类型的涡流，其中没有一个共同指示函数的单一阈值能够识别所有这些涡流类型。
A new method of extracting vortical structures from a turbulent flow is proposed whereby topological segmentation of an indicator function scalar field is used to identify the regions of influence of the individual vortices. This addresses a long-standing challenge in vector field topological analysis: indicator functions commonly used produce a scalar field based on the local velocity vector field; reconstructing regions of influence for a particular structure requires selecting a threshold to define vortex extent. In practice, the same threshold is rarely meaningful throughout a given flow. By also considering the topology of the indicator field function, the characteristics of vortex strength and extent can be separated and the ambiguity in the choice of the threshold reduced. The proposed approach is able to identify several types of vortices observed in a jet in cross-flow configuration simultaneously where no single threshold value for a selection of common indicator functions appears able to identify all of these vortex types.