SimScale CAE Forum

Mesh cells increases when coarser?

Hi there,

Having difficulty preparing my model for a CFD simulation. When making the mesh and moving the slider for fineness, I noticed at 0 the mesh estimate is 12.2M - 18.4M cells. Whereas moving to 1.7, which is more ‘fine’, this changes to 4.7M-7M cells. Why would there be more cells for a coarser mesh?

The project is trying to achieve a simulation of how the fluid moves around this robot when we submerge it into water. Keep getting stuck at simulation duration exceeds maximum runtime.

Here is a link to the project:

Appreciate any tips, thanks!

Hi @robotgrrl ,

The numbers that you see are just an estimate based on other models that have been meshed with similar settings (the estimation could be a little off).

Now, I have already seen some meshes where the cell count goes up with a smaller fineness. Reason being because the meshing tool will try to maintain a reasonable level of mesh quality when a very coarse setting is applied. So it may refine some regions further to try and preserve its quality.

The CAD model that you have seems to be a bit faulty. I can see some self-intersections and weird artifacts. For example, highlighting the edge where the mesh failed (I’m hovering over the edge name to highlight it):

Having a closer look:

Even closer:

It would be a good idea to double check the model before proceeding.