2D-meshing in cfd

A subforum specific to the development of the OpenFoam-based workbenches ( Cfd https://github.com/qingfengxia/Cfd and CfdOF https://github.com/jaheyns/CfdOF )

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oliveroxtoby
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Re: 2D-meshing in cfd

Postby oliveroxtoby » Mon Dec 17, 2018 8:48 pm

thschrader wrote:
Sun Dec 16, 2018 1:48 pm
gmsh: works fine
cfmesh: meshing error at front-window
snappyhexmesh: gives allways a 3D-mesh (?) :o
Should be fixed.
Please provide all the information requested in this post before reporting problems with CfdOF.
julieng
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Re: 2D-meshing in cfd

Postby julieng » Mon Dec 17, 2018 10:10 pm

Hello,

After compute a 3D case, in which I have boundary layers sub mesh regions, I have only access after Extract Block command to "multiblock datatest and internal mesh". I cannot choose the boundaries of interest like in the tutorial you show me.
What should I do in FreeCAD to have access to the boundaries groups in Paraview ?

Best regards

Julien
julieng
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Re: 2D-meshing in cfd

Postby julieng » Mon Dec 17, 2018 10:53 pm

I do slightly differently, I don't know why:
I can have access to the boundaries directly in the first node of Paraview Openfoam reader.
After I do the same operation than in the tutorial and finally I integrate over the surface of interest the lift and drag forces, but I think that I have to multiply the pressure calculated by Openfoam by the volumic mass of my fluid [kg/m^3] ? Right?

Best regards

Julien
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Re: 2D-meshing in cfd

Postby thschrader » Tue Dec 18, 2018 10:10 am

julieng wrote:
Mon Dec 17, 2018 10:53 pm
... but I think that I have to multiply the pressure calculated by Openfoam by the volumic mass of my fluid [kg/m^3] ? Right?
Right. See unit-definition in p dict after writing the case.
julieng
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Re: 2D-meshing in cfd

Postby julieng » Fri Nov 20, 2020 11:13 am

Hello,

I have a geometry that can be solved in 2D.

I try the 2Dboudingplane condition (try to assign the 2 planes in the same node or 2 nodes with 1 plane in each) but it doesn't work for the 3 meshers.

Image

Is this option is still supported ?

Julien
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Re: 2D-meshing in cfd

Postby thschrader » Fri Nov 20, 2020 12:00 pm

assign each face as a separate BC.
naca2412.FCStd
(405.78 KiB) Downloaded 6 times
constraint.JPG
constraint.JPG (31.73 KiB) Viewed 183 times
julieng
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Re: 2D-meshing in cfd

Postby julieng » Fri Nov 20, 2020 3:15 pm

Yes I have already done this
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Re: 2D-meshing in cfd

Postby oliveroxtoby » Fri Nov 20, 2020 3:23 pm

julieng wrote:
Fri Nov 20, 2020 3:15 pm
Yes I have already done this
Please upload your case, otherwise it's pure guesswork.
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Re: 2D-meshing in cfd

Postby julieng » Fri Nov 20, 2020 3:37 pm

The file is attached.

With the native geometry drawn with partdesign, I have several errors telling that I have to add 2Dbounding BC.

I have exported the geometry in step file and import it. I am able to run the snappyHexMesh in 2D but the result is completly wrong.

Someone can try to mesh this case in 2D please?
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Re: 2D-meshing in cfd

Postby oliveroxtoby » Fri Nov 20, 2020 8:34 pm

julieng wrote:
Fri Nov 20, 2020 3:37 pm
The file is attached.

With the native geometry drawn with partdesign, I have several errors telling that I have to add 2Dbounding BC.

I have exported the geometry in step file and import it. I am able to run the snappyHexMesh in 2D but the result is completly wrong.

Someone can try to mesh this case in 2D please?
Works for me with all three meshers if I use a base element size of 4mm. If you made the slab thicker, you could use a larger element size.