Problems with periodic/cyclic boundaries
 

Hi everybody!

I tried to convert an ICEM created .msh file to Open Foam and got some Errors. Seems like, theres anything Wrong with the perodic boundaries.


dimension of grid: 3
Creating shapes for 3-D cells
Building patch-less mesh...--> FOAM Warning :
From function polyMesh::polyMesh(... construct from shapes...)
in file meshes/polyMesh/polyMeshFromShapeMesh.C at line 577
Found 292878 undefined faces in mesh; adding to default patch.
done.

Building boundary and internal patches.
Creating patch 0 for zone: 94 start: 1 end: 3818920 type: interior name: int_LIVE
Creating patch 1 for zone: 95 start: 3818921 end: 10268062 type: interior name: int_LIVE
Creating patch 2 for zone: 96 start: 10268063 end: 10887762 type: interior name: int_LIVE
Creating patch 3 for zone: 97 start: 10887763 end: 12179520 type: interior name: int_LIVE
Creating patch 4 for zone: 98 start: 12179521 end: 14461122 type: interior name: int_LIVE
Creating patch 5 for zone: 99 start: 14461123 end: 15144828 type: interior name: int_LIVE
Creating patch 6 for zone: 100 start: 15144829 end: 15147466 type: wall name: WALLS
Creating patch 7 for zone: 101 start: 15147467 end: 15148659 type: wall name: WALLS
Creating patch 8 for zone: 102 start: 15148660 end: 15149106 type: wall name: CORE_INLET
Creating patch 9 for zone: 103 start: 15149107 end: 15150217 type: wall name: FAN_INLET
Creating patch 10 for zone: 104 start: 15150218 end: 15179078 type: periodic name: PERIODIC


fluent patch type periodic not recognised.#0 Foam::error::printStack(Foam::Ostream&) in "/home/sebastian/OpenFOAM/OpenFOAM-1.6/lib/linux64GccDPOpt/libOpenFOAM.so"
#1 Foam::error::abort() in "/home/sebastian/OpenFOAM/OpenFOAM-1.6/lib/linux64GccDPOpt/libOpenFOAM.so"
#2 main in "/home/sebastian/OpenFOAM/OpenFOAM-1.6/applications/bin/linux64GccDPOpt/fluentMeshToFoam"
#3 __libc_start_main in "/lib64/libc.so.6"
#4 _start at /usr/src/packages/BUILD/glibc-2.9/csu/../sysdeps/x86_64/elf/start.S:116


From function fluentToFoam::main(int argc, char *argv[])
in file fluentMeshToFoam.L at line 1334.

FOAM aborting

Aborted


Can anybody help me please??


Sebastian

Hi Sebastian,

I think periodic boundaries can't be converted directly into FOAM. Try importing mesh with the periodic boundaries being two normal patches. You can generate the cyclic boundary condition afterwards using the createPatch utility.

Regards,
Stefan

Periodic Boundary Entity is not not specified correctly
 

Hi everybody,

I have the same problem with periodic BC. I don't know if periodic boundaries can be converted directly into FOAM, but I get the same error when I want to import the mesh.

As I understood, I have to create "createPatch" in system folder with the following lines in it (from thread)
Code: matchTolerance 0.2; pointSync true; patches ( { name NAME1; type cyclic; constructFrom patches; patches (NAME1 NAME2); } );
I tried to defining, as Herbert said, periodic boundaries without being linked, to change it afterwards, but Gambit doesn't let me, it gime as error: "Periodic Boundary Entity NAME1 is not not specified correctly. The two periodic entities must be link meshed and specified on the same Boundary Entity" and the same for NAME2.

If the solution is just use "createPatch" utility, how I can defined the BC to use it? what in the normal patch?

Regards,
Victor

Hi Victor,

I solved it by redefining the periodic boundaries as symmetry planes. I don't know about Gambit, but I sucessfully did this in Fluent. You can also do this in TGrid.
So create your mesh with periodic boundaries. Load the mesh in fluent or tgrid and set the boundaries to symmetry. Then you have for insance two planes, symmetry_1 and symmetry_2. Use fluent3DMeshToFoam to convert this mesh. Afterwards use createPatch to make both planes cyclic.

Hope this helps.

Regards,
Sebastian

Hi everyone,

Thanks Sebastian, for answering so fast. But I am working with Gambit and OpenFoam, and importing mesh with "fluentMeshToFoam".

I defined boundaries as "patch" and export it. In OpenFoam then, I used "createPatch" to set it from "patches" to "cyclic". All of that, defining this boundaries as cyclic type in constant/p and constant/U. The error that came up:

- Attempt to cast type patch to type lduInterface

I tried to defining boundaries as "symmetry" and export it and was OK. In OpenFoam then I have to use "createPatch" to set it from symmetry to cyclic. All of that, defining this boundaries as cyclic type in constant/p and constant/U. The error that come up:

- inconsistent patch and patchField types for patch type symmetryPlane and patchField type cyclic.

* I understand that it just can use "patches" or "set" in createPatch

Can anybody help me please??

Victor

make sure that your boundary file in the constant folder is properlly set.. i mean the symmetry condition is indicated by the string "symmetryPlane" if you wanna create a cyclic patch then in the same boundary file the name has to be cyclic or cyclicAMI.. have you checked that?

Thanks calim, but no way. I told "symmetry" cause I defined boundary like that in Gambit, but this is equivalent to "symmetryPlane" into OpenFoam. That problem I got settled it like 'fs82' said here (http://www.cfd-online.com/Forums/ope...oam-1-5-a.html). I got all fine, but it came up a new error as:

- FOAM FATAL ERROR: For path NAME1 there are 40 face centres, for the neigbour patch NAME" there are 0.

I looked for something wrong into boundary folder, but it's nice. I have "nFace 20" in both.

Can anyone help me with this problem?

- FOAM FATAL ERROR: For path NAME1 there are 40 face centres, for the neighbour patch NAME2" there are 0.

sorry