Slip velocity of lattice Boltzmann simulation using bounce-back boundary scheme

In this work we investigate the issue of non-physical slip at wall of lattice Boltzmann simulations with the bounce-back boundary scheme. By comparing the analytical solution of two lattice models with four and nine discrete velocities for the force-driven Poiseuille flow, we are able to reveal the exact mechanism causing the issue. In fact, no boundary condition is defined by the bounce-back scheme for the the discrete velocities parallel to wall. Other factors, such as initial conditions and inlet and outlet boundary conditions, can play the role and induce the non-physical slip velocity. Therefore, the issue is not related to the single-relaxation-time scheme. Naturally the key for resolving it is to specify the definition for these velocities. Through a lid-driven cavity flow, we show that the solution can be as easy as no extra effort required for simple geometries, although further study is necessary for complex geometries.

No reviews yet.

No comments yet.