Refinement on very coarse mesh

Using SimScale CAD & Meshing
1

I want to simulate gas flow through a pipeline, through a long timeframe. Due to computational limit, I made the following choice:

  • Very thin 2D domain instead of 3D pipeline
  • Very coarse mesh (0.1m max length, 0.05 min length)

I got the following error message

The solution diverged, please check your simulation setup. Divergence can also be caused by bad elements in the mesh. Such elements tend to exist near walls and sharp corners. Visually inspect your mesh to locate them and re-mesh with additional refinements in their vicinity. If you are confident about the mesh-quality, please reduce relaxation factors and use more conservative numerical schemes.

I suspect that my mesh size is bigger than the height of my 2D domain, hence the error.

How can I fix that? Project link: https://www.simscale.com/workbench/?pid=3253427884872203341&mi=run%3A122%2Csimulation%3A90&mt=SIMULATION_RUN

2

Hi!

This mesh is no good!

image
image461×620 19.2 KB

I would recommend to use a criteria such as:

  • A number of elements across the shorter length (6 or more I would say, this depends on who you ask)
  • As low as possible aspect ratio

This article should also help: