TY - JOUR
T1 - Discrete unified gas kinetic scheme for all Knudsen number flows. IV. Strongly inhomogeneous fluids
AU - Shan, Baochao
AU - Wang, Peng
AU - Zhang, Yonghao
AU - Guo, Zhaoli
PY - 2020/4/8
Y1 - 2020/4/8
N2 - This work is an extension of the discrete unified gas kinetic scheme (DUGKS) from rarefied gas dynamics to strongly inhomogeneous dense fluid systems. The fluid molecular size can be ignored for dilute gases, while the nonlocal intermolecular collisions and the competition of solid-fluid and fluid-fluid interactions play an important role for surface-confined fluid flows at the nanometer scale. The nonequilibrium state induces strong fluid structural-confined inhomogeneity and anomalous fluid flow dynamics. According to the previous kinetic model [Guo et al., Phys. Rev. E 71, 035301(R) (2005)10.1103/PhysRevE.71.035301], the long-range intermolecular attraction is modeled by the mean-field approximation, and the volume exclusion effect is considered by the hard-sphere potential in the collision operator. The kinetic model is solved by the DUGKS, which has the characteristics of asymptotic preserving, low dissipation, second-order accuracy, and multidimensional nature. Both static fluid structure and dynamic flow behaviors are calculated and validated with Monte Carlo or molecular dynamics results. It is shown that the flow of dense fluid systems tends to that of rarefied gases as the dense degree decreases or the mean flow path increases. The DUGKS is proved to be applicable to simulate such nonequilibrium dense fluid systems.
AB - This work is an extension of the discrete unified gas kinetic scheme (DUGKS) from rarefied gas dynamics to strongly inhomogeneous dense fluid systems. The fluid molecular size can be ignored for dilute gases, while the nonlocal intermolecular collisions and the competition of solid-fluid and fluid-fluid interactions play an important role for surface-confined fluid flows at the nanometer scale. The nonequilibrium state induces strong fluid structural-confined inhomogeneity and anomalous fluid flow dynamics. According to the previous kinetic model [Guo et al., Phys. Rev. E 71, 035301(R) (2005)10.1103/PhysRevE.71.035301], the long-range intermolecular attraction is modeled by the mean-field approximation, and the volume exclusion effect is considered by the hard-sphere potential in the collision operator. The kinetic model is solved by the DUGKS, which has the characteristics of asymptotic preserving, low dissipation, second-order accuracy, and multidimensional nature. Both static fluid structure and dynamic flow behaviors are calculated and validated with Monte Carlo or molecular dynamics results. It is shown that the flow of dense fluid systems tends to that of rarefied gases as the dense degree decreases or the mean flow path increases. The DUGKS is proved to be applicable to simulate such nonequilibrium dense fluid systems.
KW - discrete unified gas kinetic scheme
KW - rarefied gas
KW - fluid flows
UR - http://www.scopus.com/inward/record.url?scp=85084555151&partnerID=8YFLogxK
U2 - 10.1103/PhysRevE.101.043303
DO - 10.1103/PhysRevE.101.043303
M3 - Article
C2 - 32422810
AN - SCOPUS:85084555151
VL - 101
JO - Physical Review E: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics
JF - Physical Review E: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics
SN - 1539-3755
IS - 4
M1 - 043303
ER -