Divergence of velocity field for porous media

Dear Palabos users and developers;
I hope you are doing very well.

I am trying to simulate non-Newtonian flow in a 2D porous media and I am encountering the divergence of the velocity field, the problem is after 2000-3000 iteration, the velocity became zero in most of the regions and there are anomalies with high velocities in some region (most of the time in outlet and inlet).

I also tested an example of MPLBM and I will attach the result to this post. Ux_inlet and Ux_half velocity field for a 3D sphere pack looks fine but as it could be understood from gifs, it seems that the situation is challenging for Uy and Uz.

Since I have chosen Palabos as the base software of my MSc thesis, I will be really glad if you could help me with this challenge.

Many thanks;
Elahe;

segmented150

2D non-Newtonian results

animated gifs for spherepack

I will be really honored if you could check this post.
Thank you!

@jesantos @jlatt