On the Thresholds of Vortex Identification Methods
Several vortex identification methods along with a newly proposed \(\Omega \) method are examined in the Burgers vortex and the Sullivan vortex. Of particular interest is the physical meaning of the parameter, especially the thresholds. While all the methods are capable of capturing precise vortex boundaries in these two analytical vortices, only the parameter \(\Omega \) seems to have a clear physical meaning, i.e. to what extent the local fluid particles tend to rotate like a rigid-body. Therefore, the parameter \(\Omega \) might be helpful and informative when utilized to investigate the interaction of vortical structures.
KeywordsThreshold Vortex identification \(\Omega \) method
This work was supported by the National Natural Science Foundation of China (Grant No. 11702159) and Project Funded by China Post-doctoral Science Foundation (Grant No. 2017M610876).
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