snappyHexMesh - layers in 3d pipe bifurcation
2 Attachment(s)
Hallo.
I'm trying to mesh a three-dimensional pipe bifurcation for internal flow simulations using snappyHexMesh. Problems occure concerning the additional boundary layers close to the "stagnation point" , see the pictures. I want the layers to enclose the sharp edge or to merge and go farther inwards the flow field. Has anyone an idea/suggestion how to do that? Thanks in advance for any response! Daniel |
Quote:
Best, |
Hi Daniel
How did you import the surface? Did you import one or two patches in this area? Regards fritz |
1 Attachment(s)
Quote:
Seems to me you are an expert indeed. :-) I tried varying the feature angle before but without success... However, setting the featureAngle to 310° finally worked well. Not the best mesh I have ever seen but pretty much what I wanted. Thanks a lot! But I still have problems with uneven/warped layers at some points, see figure. Increasing nSmoothThickness from 20 to 30, increasing nSmoothSurfaceNormals from 1 to 10 and increasing nSmoothNormals from 3 to 30 reduced this problem nearly everywhere but not at the red marked location. Any suggestions on that? Cheers Daniel |
Quote:
Hej Fritz. The entire wall in that area is defined by one *.stl and one patch. I tried loading two *.stl files (one for each half of the bifurcation wall) without any effect. Daniel. |
Quote:
Another way to do it would be using no surface layers in sHM and then refining the near wall mesh with refineWallLayer tool. I find it to be more robust and it gives relatively accurate mesh size at the wall. The real advantage is that you can keep using reasonable featureAngle values and have a nice surface mesh with very nice o-grids in the volume. Best, Ziad |
nihil,
how did you manage to get 1) sharp edges and 2) a visible boundary layer at your inlet? |
For layers, take a look at:
~/OpenFOAM-1.7.x/tutorials/incompressible/pimpleDyMFoam/wingMotion/wingMotion_snappyHexMesh/ Best, |
Hi nihil,
could you post us your sHMDict file? Would be interesting for me to see how you produce such almost perfect layers. I'm struggling getting good layers. Regards, Toni |
Hello everybody!
I also would like to mesh a similar pipe as you did, nihil, but i am not even half as successful. Could you please explain, how the geometry has to be, from that i have to create the stl-Files for inlet, outlet and the wall of the pipe. And how does your sHMDict look like then? Or, maybe, does anybody know, where i can find a tutorial for simulating internal flow or something? Sorry, i know this means you have to grant a big request, but i am thankful for any help, cause i feel like standing in a very long dead end street at the moment. greets Ulrich |
3 Attachment(s)
Quote:
I have the same problem. I'm doing some experiments with snappyHexMesh (in OpenFOAM 1.6) with some basic geometry (in this case a cube) and these are my results In the first picture you can see the whole geometry, I want to snap the mesh in y and z directions and maintain constant in x direction (simple extrusion). Moreover I want layers on external walls (it is like a cubical section pipe with x as axial direction). In the second and third pictures you can see respectively an x and y slice. x_slice : the layers are good on perimeter and also on the corners y_slice : the layers disappear on "inlet and outlet" faces as you can see --> How can I ''print'' the layers also on these faces?? I've defined two patches in stl file: - mypareti for external wall - inlet_outlet for inlet and outlet face (normal to x axis) here my geometry and castellatedMesh parts of snappyHexMeshDict file Code:
geometry Code:
addLayersControls |
It might not address your problem, but I would suggest to use the latest version of snappyHexMesh provided in OpenFOAM 2.0.1 (or 2.0.x). The management of surfaces improved greatly.
Best, |
Quote:
|
hi ziad
would you please tell more about how using "refineWallLayer tool" in more details? Regards. |
All times are GMT -4. The time now is 14:01. |