Imbalance-correction grid-refinement method for lattice Boltzmann flow simulations

Abstract

To enhance the accuracy and applicability of the zonal grid refinement method for the lattice Boltzmann method, a new method which minimizes the interface imbalances of mass and momentum is developed. This method introduces a correction step for the macroscopic flow variables such as the fluid density and velocity to remove their interface discontinuity. To demonstrate and evaluate the presently developed imbalance correction grid refinement method, large eddy simulations of turbulent channel and square cylinder flows are carried out. By changing the grid arrangement in the turbulent channel flows, it is confirmed that the present method reduces the sensitivity to the location of the grid refinement interface and minimizes the unphysically discontinuous profiles satisfactorily. Furthermore, the present method considerably improves mass conservation of the system, which is particularly important for long time periodical flow simulations. It is also confirmed that the present method generally improves the prediction performance of the square cylinder flows.