NEW LATTICE KINETIC SCHEMES FOR INCOMPRESSIBLE VISCOUS FLOWS

Abstract

A new two-dimensional lattice kinetic scheme on the uniform mesh was recently proposed by Inamuro, based on the standard lattice Boltzmann method (LBM). Compared with the standard LBM, this scheme can easily implement the boundary condition and save computer memory. In order to remove the shortcoming of a relatively large viscosity at a high Reynolds number, a first-order derivative term is introduced in the equilibrium density distribution function. However, the parameter associated with the derivative term is very sensitive and was chosen in a narrow range for a high Reynolds number case. To avoid the use of the derivative term while removing the shortcoming of a relatively large viscosity, new lattice kinetic schemes are proposed in this work following the original lattice kinetic scheme. In these new lattice kinetic schemes, the derivative term is dropped out and the difficulty of the relatively large viscosity is eased by controlling the time step δt or sonic speed cs. To validate these new lattice kinetic schemes, the numerical simulations of the two-dimensional square driven cavity flow at Reynolds numbers from 100 to 1000 are carried out. The results using the new lattice kinetic schemes are compared with the benchmark data.