Troubles with layer adding in my mesh
So I've been starting using OPENFoam those last days and I am a bit stuck at the layer insertion in my mesh.
First of all : I'm meshing a 3D profile (clarkypt) for some remote controlled device to know more about the ground effect on such slender body ... slender because for 1m long, I have only 0.1m of width! so it is 3D since I'm interested in 3D effects.
So for now I generated a mesh without surface layers, to keep it simple, but know, I'd like to add it to capture accurately my boundary layer.
The problem : sHM seems to be detecting that he needs to add layers ... but it clearly says : no layer extruded ... so my question is: why ?
here is the dictionnary I'm using:
and the output of SHM:
So if someone could give me a hint of were it could go wrong ... I would really appreciate it!
for now what I tried is :
play with feature Angle up to 180° : result is above,
play a bit with the mesh quality : reduce the tolerance to allow bad cells ... doesn't seem to have an effect.
I have to say that I am a bit lost!
Thanks for reading,
Looking at the output, this appears to hold the key:
Try to deactivate all the mesh quality controls for the layer insertion
So first, after the remark of mturcios, I rounded the trailing edge of my profile to get a better there (I can understand that adding such a layer on such a sharp corner can lead to sh***y cells). It did not helped a lot, so I tried by using some more permissive orthogonality settings ... and still didn't worked.
And I just tried the solution of Éloïse ... and WOW, it worked! that was a good solution! but know, new problem : how do I visualize the bad cells in paraView ? I enabled the sets, choose the nonorthoblabla set ... and nothing appeared when in the checkMesh I have this :
thanks a lot!
You'll need to do a foamToVTK and include the set. Open your mesh case in paraview, then open the VTK file that contains your cellSet (will be in the VTK folder by default)
It is not a cell set but a face set. Use the command:
foamToVTK -faceSet nonOrthoFaces -latestTimeand import the created VTK in paraView
thanks for the tips, I saw the command in one of your posts Éloïse. And so now it raises new questions!
Now it is more about the mesh quality than inserting the viscous layer but I keep posting on this topic, if a moderator thinks I should start another topic, then I'll do so!
So here is my 3D profile:
the bad faces are those ones:
as seen from the top:
and some interior mesh details:
Now I am wondering why I get those bad faces (and by the way, I do not see 976 faces ... some are missing, where do they go ?) in such "easy" location ??
what are the parameters to tune up to get a very correct mesh (and you can also see that the snapping kinda deform the geometry but I have to play with sHM to solve this with featureEdges I guess)
So every advice is appreciated!
And by the way a more general question on the limits of OpenFOAM : what is a very bad grid (orthogonality, skewness etc ..) for openfoam ?
Thanks a lot for your time,
Have you tried Feature Edge Handling
I guess this will fix your problem
same topic, different problem
Hi everyone, I've got a problem with my layer addition in SHM. I've read a lot about the whole topic, but never heard something about this problem. Perhaps you could help me out.
I am meshing a wind turbine an therefore used SHM, especially the new snapEdge feature of SHM (nFeatureSnapIter). The results for time 2 are very good, but when it comes to layer addition, some "undo"-iterations occur which destroy some of the snapped edges. Furthermore in some of these regions (and only there!) no layers are added. All my checkMesh controls are disabled. I am using a featureAngle of 180.
Problem with featureEdge feature
I don't know if this thread is still being watched, but I will give it a try anyway...
Did you solve this problem? I am experiencing the same behaviour of SHM with a ship hull geometry, and the more layer addition iterations I allow to SHM, the less cells are extruded, resulting in a grid almost without any layers. I experimented a lot with all the settings in the layer addition part, but I cannot get better than about 85% of extruded cell layers. Unfortunately, the 15% of layers are missing in quite essential parts. Do you have any helpful hint?
|All times are GMT -4. The time now is 23:39.|