Improving mesh quality near sphere/sphere and sphere/wall contact points
I would like to study the diffusion across the porous surface that results from the Boolean subtraction of a set of spheres from a box. At the contact points of the spheres, there are very highly skewed mesh elements. Dixon, in "Systematic mesh development for 3D CFD simulation of fixed beds: Contact points study" (https://doi.org/10.1016/j.compchemeng.2012.08.011) talked about four options:
- shrinking particles
- enlarging particles
- locally removing a spherical cap near the contact points
- locally forming a cylindrical bridge
The first two are pretty easy to implement but reduce the accuracy of the final results. The third and fourth are more accurate but require detecting where 2D surfaces are within a certain tolerance and then locally modifying the surfaces.
Does gmsh include any options that force these types of mesh refinements?