Evaluation of forcing schemes in pseudopotential based multiphase lattice Boltzmann model

Abstract

For the past two decades LBM has been interest of research for handling multiphase and multicomponent fluid flows. The pseudo-potential model is a widely used multiphase Lattice Boltzmann model based on the Equation of State (EOS) proposed by Shan and Chen. In the multiphase LB model, an interaction force between the molecules is being incorporated using a forcing scheme that automatically cause phase separation without tracking the interface. In this paper three different forcing schemes: the Discrete Force Method, Velocity Shift Method and Exact Difference Method are evaluated to study their effect on relaxation parameter. The spurious currents are estimated for different values of relaxation parameters. SCEOS is found to be stable with all forcing schemes at lower liquid to gas density ratios when viscosity ratio is set to unity. Numerical simulations were performed on D2Q9 lattice structure. The density and kinematic viscosity ratios between the liquid and gas phases were maintained at 50 and 5 respectively.