title: Evaluation of a lattice Boltzmann method in a complex nanoflow.
abstract: In order to establish a cost-effective strategy to simulate complex flows in continuum to slip and transitional regimes, the present study assesses the performance of a lattice Boltzmann method (LBM) formerly discussed by the present authors' group [Niu, Phys. Rev. E 76, 036711 (2007)]. This LBM is based on a diffuse scattering wall boundary condition, a regularization procedure, and an effective relaxation time associated with the Knudsen number. The present assessment is on its regularization procedure and third-order truncated system based on the two-dimensional twenty-one discrete velocity (D2Q21) model for the Cartesian lattices. The test flow cases are force-driven Poiseuille flows, the Couette flows and a flow around a square cylinder situated in a nanochannel. For producing the reference data of the square cylinder flow, the molecular dynamics simulation using Lennard-Jones potential is also performed. Although the flow profiles and the slip velocities of the Poiseuille flows and the Couette flows are more accurately predicted by the third-order truncated system, the general velocity profiles around the square cylinder are also well predicted by the second-order truncated system based on the two-dimensional nine discrete velocity (D2Q9) model. It is also confirmed that without the regularization process, the entire flow field prediction suffers unphysical momentum oscillations around the square cylinder.
authors.affiliation: Department of Mechanical Engineering, Osaka Prefecture University, Sakai, Osaka, Japan. suga@me.osakafu-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Suga
authors.forename: S
authors.initials: S
authors.lastname: Takenaka
authors.forename: T
authors.initials: T
authors.lastname: Ito
authors.forename: M
authors.initials: M
authors.lastname: Kaneda
authors.forename: T
authors.initials: T
authors.lastname: Kinjo
authors.forename: S
authors.initials: S
authors.lastname: Hyodo