Exploring multiple phases and first-order phase transitions in Kármán Vortex Street  

作　　者：Xu Li Xing Xiang Tingting Xue Limin Wang Xiaosong Chen 

机构地区：[1]School of Systems Science and Institute of Nonequilibrium Systems,Beijing Normal University,Beijing 100875,China [2]State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy ofSciences,Beijing 100190,China [3]School of Chemical Engineering,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2024年第11期47-54,共8页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No.12135003)。

摘　　要：Kármán Vortex Street, a fascinating phenomenon of fluid dynamics, has intrigued the scientific community for a long time. Many researchers have dedicated their efforts to unraveling the essence of this intriguing flow pattern. Here, we apply the lattice Boltzmann method with curved boundary conditions to simulate flows around a circular cylinder and study the emergence of Kármán Vortex Street using the eigen microstate approach, which can identify phase transition and its order-parameter. At low Reynolds number, there is only one dominant eigen microstate W_(1) of laminar flow. At Re_(c)^(1)= 53.6, there is a phase transition with the emergence of an eigen microstate pair W^(2,3) of pressure and velocity fields. Further at Re_(c)^(2)= 56, there is another phase transition with the emergence of two eigen microstate pairs W^(4,5) and W^(6,7). Using the renormalization group theory of eigen microstate,both phase transitions are determined to be first-order. The two-dimensional energy spectrum of eigen microstate for W^(1), W^(2,3) after Re_(c)^(1), W^(4-7) after Re_(c)^(2) exhibit-5/3 power-law behavior of Kolnogorov's K41 theory. These results reveal the complexity and provide an analysis of the Kármán Vortex Street from the perspective of phase transitions.

关 键 词：Kármán Vortex Street first-order phase transition eigen microstate approach renormalization group theory of eigen microstate 

分 类 号：O35[理学—流体力学]