CFD Online Discussion Forums - [mesh manipulation] Converting a 2Dmesh to axisymmetric

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- - [mesh manipulation] Converting a 2Dmesh to axisymmetric (https://www.cfd-online.com/Forums/openfoam-meshing/61473-converting-2dmesh-axisymmetric.html)

Hi again..

as reported before, I have the problem, that after MAM checkMesh or collapsEdges crashes with a floating Point Exception. I had this issue before but could solve it, by modifying the boundary of the mesh.
Now I am facing this problem again, but cannot figure out, where the problem comes from. I'd be glad if someone could check the case.
https://dl.dropbox.com/u/587565/gly8...wBackup.tar.gz

Thanks in advance!
Lindstroem

Quote:

Originally Posted by lindstroem (Post 375985)

Can't reproduce your problem. MAM and collapseEdges work without problem for me. Could you be more specific about the OF-version you use and the exact commands you used

Hi Bernhard,

thanks for your help. Your posting made me starting from the scratch again. The problem was that I used the MAM-version for 1.4.1 to 1.7.x although my OF-version was 2.0.0. I had a wrong alias.
I always thought it was a problem of my case!

Thanks!!

plz help me dear foamers:

Hi foamers.
I am trying to convert the 2D mesh to 3D!
my real geometry is (pic1) but i want to Use 2D for my solver(because in 3D very slow Running speed) ,and for this reason i made 2D(pic2).
can I Change the type of frontAndBack and make 2D to 3D (pic3)???
my width 44mm.

Hello Vahid,

the width of your geometry does not matter (as you want to run a 2D simulation, if it does matter, it is not 2D anymore). Just make sure, it is only one cell big.
Yes, frontAndBack should be of type empty.

Greetings

Hi lindstroem ,thanks for your answer.
your answer means should I use 3D geometry ???(because width of my real geometry is 44mm!!!)

Hi again,

two general things:
- OpenFOAM uses for 2D simulations a mesh with only one cell in the "z-direction" (or which axis you choose to be perpendicular to the 2D-plane you simulate).
So the mesh is basically 3D, but the boundaries (defined as empty) indicate for OF that it is a 2D case. (see U-126 in the User guide)

- if you do a 2D simulation, your depth is "infinite". Otherwise it would be 3D if you want to account for the dependence on the depth. So you should make yourself clear what you want to simulate.

I cannot recommend you what you should do, because it depends on what you want to solve for.

Hi Dear lindstroem .
thanks a lot for your Clear answer.

Hi
I start OF recently. I have O.F 1.5 dev . I download makeAxialmesh and try compile it according to threads but some errors appear (repatchPolyTopoChanger.H file error)
please guide me for compiling this utility step by step. (specific paths ; specific commands ...)

Quote:

Originally Posted by ali jafari (Post 383458)

I've got to give the question back: which version of makeAxialMesh did YOU download?

Anyway: try getting this version (according to the README it should work with 1.5-dev but I can't check because I don't have such an old installation) with the following command

svn checkout https://openfoam-extend.svn.sourcefo...MakeAxialMesh/

go to the makeAxialMesh-directory and do the usual wmake. But all that is described on http://openfoamwiki.net/index.php/Contrib_MakeAxialMesh anyway

Quote:

Originally Posted by amin144 (Post 356157)

Hello Dear Foamers:)
Especially Dear Bernhard;)

I want to run testCase and doing below steps:
(I think this thread need a post that describe process step by step like this:()

(My OF version: openFoam 1.5-dev)
1-Download files of utility and after Compile makeAxilMesh using "wmake all"---> well done
2-Download "testCase" files
3-Go to testCase Directory
4-Run "blockMesh"----> well done
5-Run "makeAxialMesh -axis movingWall -wede frontAndBack -overwrite" --->well done
6-Run "paraFoam" and can see wedge shape grid
7-Run "collapseEdges 0.0001 175 -overwrite" shows below message:

Create time

Create polyMesh for time = 0

Merging:
edges with length less than 0.0001 meters
edges split by a point with edges in line to within 175 degrees

Collapsing 21 small edges
Morphing ...
Collapsing 0 small edges
Collapsing 0 in line edges
Max face area:4.36194e-05
Collapse area factor:1e-09
Collapse area:4.36194e-14
Collapsing 0 small high aspect ratio faces
Writing collapsed mesh to time 0
End

8-Run "icoFoam" and it runs without any problem!

-----------------------------------------------------
-----------------------------------------------------
Queations:

1))Is my Steps all True? Isn't anything wrong?

2))What does this Case physically show ? Only a full closed cylinder whitout any flow?

3))Any body can mail me a test case for Flow in a simple axisymmetric pipe?
I will appreciat if anybody upload a pipe case for using everyone for test beside this simple and maybe unused case :(

-------------------------------------------------------
-------------------------------------------------------
shariatkhah@gmail.com

Thanks:)

-----------------------------------
I do your steps but when I run parafoam and click on apply . parafoam exiting and this error appears :
--> FOAM FATAL IO ERROR:
inconsistent patch and patchField types for
patch type symmetryPlane and patchField type zeroGradient

file: /home/ali/USER_RUN/tutorials/axialCavity/0/p::boundaryField::movingWall from line 34 to line 34.

From function fvPatchField<Type>::New(const fvPatch&, const DimensionedField<Type, volMesh>&, const dictionary&)
in file /home/opencfd/OpenFOAM/OpenFOAM-2.1.1/src/finiteVolume/lnInclude/fvPatchFieldNew.C at line 164.

FOAM exiting

Segmentation fault (core dumped)
-------------------------------------------------------------
I use checkMesh after blockMesh and that's OK , and I use checkMesh after makeAxialMesh but it show
" Failed 4 mesh checks."
how do I understand that I compile MakeAxialMesh correctly ?

Dear Ali
Did you tested testCase or another case?
what is your OF version?

Quote:

Originally Posted by amin144 (Post 384108)

Dear Ali
Did you tested testCase or another case?
what is your OF version?

I used testcase. I use openfoam2.1.1 because makeaxialmesh didn't compiled on OF 1.5-dev !!

I think you should reinstall you OF 1.5 dev
and you couldn't run test case or your case?
I can't understand.

feel free to mail me:
amin_144@yahoo.com

AnyOne have tested makeAxialMesh in OF 2.1.1 ?

Hi Dear Foamers!

AnyOne have tested makeAxialMesh in OF 2.1.1 ?
I have used it in 1.5dev before and it worked correctly as I said in my other posts in this thresd.
but today I used it in OF 2.1.1
I compiled the version which is written for OF 2.0.0 and there isn't especial version of makeAxialMesh for OF 2.1.1 !!
but when I ran "check mesh" (after collaspsing edges) it shows an error:

***Wedge patch frontAndBack_pos not planar. Point (0.005 0.06 0.00174478) is not in patch plane by 3.9962e-08 meter.

Any change in code of this utility is needed for OF 2.1.1 ?
TanX very much

Hi Amin,

I have had this problem before, you shouldn't need to change anything.
See posts between Bernhard and myself in this threat, (post #106 onwards)

Kind Regards,
Tom

Hello everybody, just one question is it possible to create a geometry that is symetric around a coordinate axis and not around one of its boundaries?

Thank you!

Quote:

Originally Posted by emil (Post 391828)

Hello everybody, just one question is it possible to create a geometry that is symetric around a coordinate axis and not around one of its boundaries?

Thank you!

What do you mean with "not around one of its boundaries"? Could you sketch it?

Hello,

I managed to avoid it by creating wedge (5 degree slice) mesh in Gambit and then importing it into OpenFoam. I hope that procedure is ok.

And what I ment is if the domain is ofset from x-axis for some measure and I want to revolve it around x-axis and not the boundary

Thank you

rotationDict Confusing

What is the difference between new mode and old mode...Pls somebody explain it.