Comparison of Liutex and Other Vortex Identification Methods Based on Vortex Models

Liutex is a newly proposed concept that represents vortex. Liutex correctly provides the rotation axis direction and the angular speed. Although many researchers have tested and verified the merit of Liutex, their applications are mostly complicated cases to which people do not have a deep understanding. This paper studies Liutex and some other vortex identification methods based on potential, Rankine, Lamb-Oseen, Taylor, and Burgers vortex models that have analytical solutions. The relations between Liutex and other vortex identification methods are also provided in this paper. Through analyzing the rotation period and vortex core regions, Liutex does not only correctly reveal the vortex core regions but also the rotation period.