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-   -   snappyHexMesh - Poor surface (http://www.cfd-online.com/Forums/openfoam-meshing-snappyhexmesh/91487-snappyhexmesh-poor-surface.html)

drrbradford August 12, 2011 06:08

snappyHexMesh - Poor surface
 
3 Attachment(s)
I'm trying to mesh an axisymmetric slender body (a finless missile) using snappyHexMesh. I have a very high quality .stl file and have modified the motorBike snappyHexMeshDict rather than write from scratch as I'm just getting to grips with openFoam. However, when I run sHM I get a very low quality surface as can be seen in the attached image for the first and second 'timestep' during sHM.

What I would like to know is which parameter in which Dict is it that controls the quality of the surface matching? I would be inclined to say that increasing the grid resolution in blockMeshDict would help. If this is so, is it possible to create a blockMesh cuboid around the missile geometry of high resolution which is contained within a larger domain cuboid? (See attached image)

drrbradford August 12, 2011 07:20

OK, so it looks like I hadn't told sHMDict to refine the surface, only the refinement area.

Before I had:
Code:

refinementRegions
    {
        refinementBox
        {
            mode inside;
        levels ((0.5 1));
        }

    }

But now I have
Code:

refinementRegions
    {
        refinementBox
        {
            mode inside;
        levels ((0.5 1));
        }
motorBike
      {  mode distance; 
          levels ((0.0001 6) (0.001 5) (0.01 4) (0.1 3) (0.2 2));
      }
    }


sasanghomi March 16, 2014 12:43

Hi Daniel ,Have you solved the problem? Have you gotten a high quality surface? Actually I have a problem similar to you!!

Best regards,
Sasan.


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