fluent patch type periodic not recognised although no periodics are defined
 

Hello there

i have a little problem while converting a mesh, created with gridgen with the fluentMeshToFoam command.
i want to simulate a 2D convergent-divergent axisymmetric nozzle. therefore i first created just one half of the 2D model. So i have 4 boundaries, one wall in the shape of the nozzle, one symmetrie plane as the axis, inlet and outlet. when i want to convert that mesh file everything works just fine the way it should.

but when i want to convert the meshfile for the whole 2D nozzle openfoam complains about periodic patches. but i dont have any periodic or symmetry boundarys, just the upper and lower nozzle wall, inlet and outlet. thats why i am a little bit confused about the error and not really shure about what to do.

i do know that during the lexing he mentions an periodic patch, but i don't know why, because the only boundary conditions set in gridgen are wall, velocity-inlet and pressure-outlet.


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Reading header: "exported from Gridgen 15.10R1"
Dimension of grid: 2
Number of points: 1798
number of faces: 3507
Number of cells: 1710
Reading points
Other readCellGroupData: 2 1 6ae 1 3
Reading uniform cells
Read zone1:2 name:fluid patchTypeID:fluid
Reading zone data
Embedded blocks in comment or unknown: (
Found end of section in unknown:)
,Reading uniform faces
Read zone1:3 name:interior-3 patchTypeID:interior
Reading zone data
Embedded blocks in comment or unknown: (
Found end of section in unknown:)
,Reading uniform faces
Read zone1:4 name:periodic-4 patchTypeID:periodic
Reading zone data
Embedded blocks in comment or unknown: (
Found end of section in unknown:)
,Reading uniform faces
Read zone1:5 name:shadow-5 patchTypeID:shadow
Reading zone data
Embedded blocks in comment or unknown: (
Found end of section in unknown:
,Reading uniform faces
Read zone1:6 name:velocity-inlet-6 patchTypeID:velocity-inlet
Reading zone data
Embedded blocks in comment or unknown: (
Found end of section in unknown:
,Reading uniform faces
Read zone1:7 name:pressure-outlet-7 patchTypeID:pressure-outlet
Reading zone data
Embedded blocks in comment or unknown: (
Found end of section in unknown:)
8 (1 8 4 5Embedded blocks in comment or unknown: (
Found end of section in unknown:
8 (1 2 4 5Embedded blocks in comment or unknown: (
Found end of section in unknown:
8 (1 9 4 5Embedded blocks in comment or unknown: (
Found end of section in unknown:)
8 (1 26 4 5

FINISHED LEXING


dimension of grid: 2
Grid is 2-D. Extruding in z-direction by: 0.0223607
Creating shapes for 2-D cells
Building patch-less mesh...--> FOAM Warning :
From function polyMesh::polyMesh(... construct from shapes...)
in file meshes/polyMesh/polyMeshFromShapeMesh.C at line 619
Found 3594 undefined faces in mesh; adding to default patch.
done.

Building boundary and internal patches.
Creating patch 0 for zone: 3 start: 1 end: 3333 type: interior name: interior-3
Creating patch 1 for zone: 4 start: 3334 end: 3390 type: periodic name: periodic-4


--> FOAM FATAL ERROR:
fluent patch type periodic not recognised.

From function fluentToFoam::main(int argc, char*argv[ ])
in file fluentMeshToFoam.L at line 1344.

FOAM aborting




hopefully someone has a clue how to solve my problem.

thanks a lot!

Bando

Hi,
I am not clear about your geometry, can you please post some of your geometry picture?

have you tried your case with blockMesh?

upper and lower nozzle wall??????

if I understood correct you should have symmetryPlane in the bottom, since it is a one half of your 2D model, how it can be a wall?.

Thanks,
Aadhavan

i first tried to convert the mesh for only a one-half model of the nozzle. there i have a wall and a symmetry plane. with that case the conversion of the mesh works perfectly.
but when i mirror the geometry to get a full 2d nozzle, i no longer have a symmetrie plane but 2 walls. while trying to convert the mesh of the full 2d model, openfoam starts to complain about periodics :(

is it possible to use blockMesh on a converted mesh?? or what did u mean?

in the attached file u see the one-half model of the 2d nozzle (but simulated with starccm)

Hi,
You no need to use blockMesh command for the converted mesh.
blockMesh is openFoam native meshing tool. If your geometry is simple then you can create your geometry and mesh using blockMeshDict. you no need to use other meshing tool.

this is only suggestion, just re create your mesh with whole geometry. dont mirror the half of the geometry.

Thanks,
Aadhavan

Hey Guys,
i am not shure, if this is the right place to write this, because there were several posts with a compareable problem but ill try here:

i had a problem with the FluentMeshToFoam function and periodic too.
but it seems as if i solved this like that:
1.creation of the 2d Mesh in ICEM with periodic boundary conditions,
2.export to fluent,
3.open Mesh with EDITOR
4.search for any "periodic" written in the file and change those
5. save in openFoam Case folder
6. execute FluentMeshToFoam
7. done

of cause, if a periodic BC is needed, there are functions for generating periodic BC in openfoam afterwards (i hope)

give it a shot.
i think somewhere is written periodic in the .msh file and it seems like openFoam doesend like that

i hope it works!

greetings,
micha