How to get good mesh quality？

SPIS
1

Dear All，
What‘s real meanings of the mesh quality？ How the mesh quality affect the simulation tesults？
What’s the facters affect the mesh quality? How could I get the better mesh quality? Is the samller mesh size the better?

Best Regards，
Guan

2

Hey Guan.

Mesh quality usually improves the simulation as for to my knowledge but not to a greater extent. This is usually done by making the mesh volumes/areas or more “equal” in size between portions of the mesh and thus improves the resolution.

Usually what I do is that I always use the “optimize” and “optimize (Netgen)” options in GMSH to further improve the mesh. Otherwise a good tip would be to decrease the mesh-node size around areas of interest, (for example the thruster exhaust or the surface of a spacecraft or an instrument etc.) and then let the boundary exteriour be of greater mesh size to improve simulation time. This is done by selecting a value for the points defining the structure in GMSH (point(x,y,z,k), where k is the resolution node size for this point, reducing k means a more fine mesh at this connection.

If you can and have the possibility, please attach a picture or even the .geo file of the structure you want to mesh and I could take a look at it.

Best
Silje

1 Like
3

Dear Guan,

a tetrahedron quality of 1 is reached for regular tedrahedron, whereas a quality of 0 correspond to a flat tetrahedron (i.e. a triangle). For the Poisson solution, having a more regular grid helps a bit to reach the solution, but the most important effect is for the particle pusher: if the mesh quality is too bad (too much flat tetrahedrons) particles may “jump” over some tetrahedrons and get lost. This may lead to totally unstable and/or unphysical simulations.
To improve the quality, the solution proposed by Silje is indeed the best choice.
Best Regards,
Sébastien

4

Hey Silje,
Thank you very much! That’s very useful suggestion.

Best Regards,
Guan

5

Dear Sebhess,

Thank you very much for the explanation about the quality of mesh. And Silje’s suggestion could make the mesh better.

Best regards,
Guan