Singular matrix detected

Thank you for your patience. I don’t have a solution yet, but this is probably due to a bad mesh. Others may provide additional guidance.

A few points:

  1. The STL file looks better, but look at the output:
    STL file(s) successfully read.
    Total number of facets read =134588
    Number of valid facets =104889
    Number of ignored facets = 29699

This is an indication small triangles are still present. You may get better results by reducing the facet angle tolerance and decreasing the intersection tolerance.

  1. You are still modeling the outside of the geometry. Make sure you look at the mesh by saving a vtk file. Uncheck the “External Flow” box in Mesh> Mesher

  2. Your domain box cuts the stl on the side. Increase the x and z range to ±0.296 m

  3. Some of the mesh tolerance will need to be adjusted due to the highly stretched nature of the mesh.