CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Meshing & Mesh Conversion

[snappyHexMesh] No layers from snappyHexMesh

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 18, 2018, 09:45
Default No layers from snappyHexMesh
  #1
New Member
 
Timo
Join Date: May 2018
Location: Delft
Posts: 8
Rep Power: 4
aerospacious is on a distinguished road
Dear fellow Foamers,


I'm still quite new to OpenFOAM and am using snappyHexMesh to mesh to mesh the flow over a small blended wing body.
The results from the first two parts of sHM, being the castellatedMesh and snapping algorithms, are quite fine without many (say less than 5) non-orthogonality or other illegal faces.
However, when I try to add layers I never seem to get any, or way to few (layers << 1).
I've tried playing around with all the parameters from addLayersControls, but nothing seems to work.

my sHMDict:
Code:

addLayersControls
{
    layers
    {
        BLB
        {
            nSurfaceLayers 15;
        }
    }

    relativeSizes       false; // false, usually with firstLayerThickness
    expansionRatio      1.5;
    firstLayerThickness 8e-6;
    //finalLayerThickness 0.7;
    minThickness        1e-06;


    minMedianAxisAngle    80;
    //maxThicknessToMedialRatio    0.6;
    //maxFaceThicknessRatio    0.6;

    featureAngle     180;
    
    nSmoothSurfaceNormals    50;
    nSmoothNormals    50;         
    nSmoothThickness    300;

    nRelaxIter        30;
    nLayerIter         50;
    nRelaxedIter    30;

}
Perhaps an sHM expert can already see what's going wrong from the above code, but in case you need more info I attached my full sHMDicts and logs as well. The ones with the _coarse extension are on a coarser (1.5E6 instead of 9E6) mesh.


It would therefor be really helpful if somebody with more sHM experience can tell me what I'm doing wrong.
Thanks in advance!

Timo
Attached Files
File Type: zip sHMDicts_and_logs.zip (37.1 KB, 2 views)
aerospacious is offline   Reply With Quote

Old   June 18, 2018, 12:21
Default
  #2
Senior Member
 
anonymous
Join Date: Jan 2016
Posts: 340
Rep Power: 8
simrego is on a distinguished road
Hi!


I'm not an sHM expert, but I share my experiences with you, maybe it can help.
First of all, try to add less layers once. Try with 3-5 layers. Then another 3-5 layers, etc...
Also try with relativeSizes true; Usually like this shm can generate more layers.
Try with less and greater layers (ie 1-2 layers with 0.5 relativeSize), which is easier to generate. If it will also fail somewhere, you will know the problematic regions.


Also in OpenFOAM by esi group (ie.: v1712, the latest), you can use a different mesh shrinking algorithm (using displacementLaplacian instead of medialAxis) which works much better at the sharp edges. So if you have it, you could try it.


Or if you are really lost, try cfMesh. It can generate the BL with 100% coverage and it is really simple to use, and it can generate a really nice mesh. (Also included in v1712, but you can download it for v5.0 too.)
simrego is offline   Reply With Quote

Old   June 25, 2018, 05:36
Default
  #3
New Member
 
Timo
Join Date: May 2018
Location: Delft
Posts: 8
Rep Power: 4
aerospacious is on a distinguished road
Hey Simrego,


Thanks for the fast reply! Sorry I didn't respond sooner, I overlooked my mailbox.
I'll definitely have a try at this quite soon and will let you know how it goes.
aerospacious is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
[snappyHexMesh] Old and busted: snappyHexMesh and add layers with edges Siassei OpenFOAM Meshing & Mesh Conversion 6 August 14, 2018 18:33
[snappyHexMesh] Triangular elements in boundary layers generated by snappyHexMesh mike.franky OpenFOAM Meshing & Mesh Conversion 0 June 3, 2018 09:46
[snappyHexMesh] 2D snappyHexMesh with layers grjmell OpenFOAM Meshing & Mesh Conversion 2 May 27, 2013 12:00
[snappyHexMesh] Adding layers goes wrong with SnappyHexMesh Elise OpenFOAM Meshing & Mesh Conversion 1 April 22, 2013 02:32
[snappyHexMesh] SnappyHexMesh doesn't succeed in adding several layers eti0123456789 OpenFOAM Meshing & Mesh Conversion 5 April 9, 2013 02:36


All times are GMT -4. The time now is 22:33.