Baffle / Pressure loss

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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suRe
Posts: 4
Joined: Thu Oct 04, 2018 3:46 pm

Baffle / Pressure loss

Postby suRe » Thu Oct 04, 2018 3:53 pm

Hey everybody,
can someone explain to me, how the fluid boundary "baffle" works and how it is correctly applied in FreeCAD/CfdOF.
What i would like to do is the following simple example:
I modelled a straight pipe (3000 mm long, 150 mm diameter) in which a perforated plate would be installed (currently through a second .stp File in the middle of the pipe). Since i don't want to mesh every whole of the plate, i tried adding a fixed value for pressure loss (selected the face of the second .stp File), but OF quits with errors. Is there any example on how to implement a pressure loss?
Thank you for any help!
suRe
Posts: 4
Joined: Thu Oct 04, 2018 3:46 pm

Re: Baffle / Pressure loss

Postby suRe » Thu Oct 04, 2018 6:55 pm

Well, f*ck me! On the tutorial page (opensim) is pretty much exactly the kind of example i was looking for the last 3 days.
For anyone who is looking for this particular problem in the future, here is the link.
https://github.com/opensimsa/opensim/tr ... PorousFlow
Case closed :-)
suRe
Posts: 4
Joined: Thu Oct 04, 2018 3:46 pm

Re: Baffle / Pressure loss

Postby suRe » Fri Oct 05, 2018 2:59 pm

Hey guys,
i got to revise my last comment. The example I mentioned works perfect for meshing with gmsh, but with cfmesh i just can't get it to run.
Could someone help me? Attached you will find the file.
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oliveroxtoby
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Re: Baffle / Pressure loss

Postby oliveroxtoby » Fri Oct 05, 2018 3:10 pm

suRe wrote:
Fri Oct 05, 2018 2:59 pm
Hey guys,
i got to revise my last comment. The example I mentioned works perfect for meshing with gmsh, but with cfmesh i just can't get it to run.
Could someone help me? Attached you will find the file.
cfMesh doesn't support baffles and internal regions, so snappyHexMesh must be used. Please note there are separate tutorials for snappy and gmsh - the geometry has to be set up a bit differently for the two.
suRe
Posts: 4
Joined: Thu Oct 04, 2018 3:46 pm

Re: Baffle / Pressure loss

Postby suRe » Fri Oct 05, 2018 3:43 pm

oliveroxtoby wrote:
Fri Oct 05, 2018 3:10 pm
cfMesh doesn't support baffles and internal regions, so snappyHexMesh must be used. Please note there are separate tutorials for snappy and gmsh - the geometry has to be set up a bit differently for the two.
Oh.. okay :( Too bad, i really like the meshes cfmesh generates. Even in bigger models with thousands of faces the mesh quality is very good for a free mesher. Will they be adding such a feature?