[GerhardHolzinger]

That way just a thought to demonstrate where the error messages from checkMesh come from. So thats not essential to run the case.

Moving the node is also not applicable to real-world cases, because it would be first of all a horror and secondly a vast un-expiring source of error.

However, if you think about how OpenFOAM does local mesh refining, then you also introduce hanging nodes into your mesh.

o------o-----o
|xxxx |xxxx|
o--o--o--o--o
|x |x | x |x |
o--o--o--o--o


If you want to learn more about OpenFOAM, play around with it and study the sources. You have to do this on your own.

Others can teach you, but you have to learn.

[Clément_G]

Hello openFoamers,


I just have tried to use the extrudeMesh utility to extract only one cell in the z-direction of a 3D domain in order to reduce the number of cell. Then I want to check the mesh quality of the new extrusion?


Here below: the results of the checkMesh

 

Checking geometry...
    Overall domain bounding box (-150 -50 0) (50 50 0.1)
    Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
    Mesh has 3 solution (non-empty) directions (1 1 1)
    Boundary openness (-5.65759e-20 1.68847e-19 -8.78095e-15) OK.
    Max cell openness = 2.31794e-16 OK.
    Max aspect ratio = 52.9876 OK.
    Minimum face area = 8.35319e-06. Maximum face area = 0.260762.  Face area magnitudes OK.
    Min volume = 8.35319e-07. Max volume = 0.0260762.  Total volume = 1998.9.  Cell volumes OK.
    Mesh non-orthogonality Max: 64.9 average: 3.05361
    Non-orthogonality check OK.
    Face pyramids OK.
    Max skewness = 1.39075 OK.
    Coupled point location match (average 1.42672e-14) OK.
    Face tets OK.
    Min/max edge length = 0.00295946 0.521806 OK.
    All angles in faces OK.
    Face flatness (1 = flat, 0 = butterfly) : min = 1  average = 1
    All face flatness OK.
    Cell determinant (wellposedness) : minimum: 0 average: 6.80634e-38
 ***Cells with small determinant (< 0.001) found, number of cells: 240189
  <<Writing 240189 under-determined cells to set underdeterminedCells
 ***Concave cells (using face planes) found, number of cells: 1814
  <<Writing 1814 concave cells to set concaveCells
    Face interpolation weight : minimum: 0.16318 average: 0.488491
    Face interpolation weight check OK.
    Face volume ratio : minimum: 0.147726 average: 0.956426
    Face volume ratio check OK.

Failed 2 mesh checks.

1st question: I wonder if the "Failed 2 mesh checks" are a real problem for the running of a komegaSST solver or another solver? I enclose a screenshot of the extruded mesh of my airfoil to help to picture the situation of the Mesh.



2d question: I wonder to which extend the "aspect ratio" influence the convergence (duration and success) of a calculation and sometimes makes the solver crash. Before the extrusion I had a "Max aspect ratio" equal to 5.8 but after the extrusion I get a "Max aspect ratio" of 53 (in red above)! What do you think about this topic?


Thank you for your answer.


Clément

[mactone]

May I know what tool do you use to visualize the blockMeshDict?