simpleFoam is not converging at high flow rate
 

Hello All,

I am using simpleFoam (OpenFOAM version 6.0) to solve fluid flow in porous media (also called digital rock). My simulation results could match the experimental data at low flow rate very well. But I am having issue with running high flow rate. The convergence plot is attached.

More details:
laminar;
All the cells have the same shape (cubes) and the same volume.

For the fvSchemes and fvSolution, I am mainly using the default settings from the tutorial:
$FOAM_TUTORIALS/incompressible/simpleFoam/pitzDaily

I tried to refine my mesh and my cell number reached 10^8. But it is still not converging.

I think I will try to add turbulent model.

Your comments would be greatly appreciated!

Thanks!
Min