Lattice Boltzmann method for the simulating transient extrudate swell^*

In this paper a new approach is developed to simulate the extrudate swell of viscoelastic fluid. Lattice Boltzmann model is used to solve the complex Navier-Stokes equations and constitutive equations simultaneously at each time iteration. The type of cell is re-initialized by calculating the mass fluxes between neighboring cells after each iteration. The boundary conditions are treated with the non-equilibrium extrapolation method. Finally, by tracking the moving interface, the shape of the extrudate swell is acquired.