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Old   March 11, 2011, 03:51
Default ANSA to OpenFoam
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Dear all,

I want to create a simulation in ANSA, solve it with OpenFoam and ParaView as the Post-Processor.
I want to simulate a flow. Now I have several questions:
- Do I have to be careful with the selection of element types? Has OpenFoam problems with, for example tetras,...?
- Can I set all boundary conditions in ANSA and "just" solve with OpenFoam or are there several setting OpenFoam needs to solve?
- What is the best data file I should choose for the export file from ANSA to OpenFoam?

I have studied several tutorials, also the bend_pipe tutorial, where the solver controls (controlDict, fvSchemes, fvSolution etc) are used.
- What are these solver controls? Can I use them for my simulation too, or do I first have to understand and edit them?

I hope someone can helpe me. If there are any point where I have to get more precise, please let me know.

EDIT:
The result of the simulation should be to know how the air streams and to describe the heat transfer to a surface overflown by the air.
- Which OpenFoam-solver is the best to choose?

The three directories required to run an application are constant, system and time - directories. Is one of them created by ANSA, f.ex. the constant?


Regards,
tH3f0rC3

Last edited by tH3f0rC3; March 11, 2011 at 04:32.
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Old   March 11, 2011, 16:29
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Vangelis Skaperdas
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Hi Dirk,

The mesh type depends on the complexity of your geometry.
If it is simple, use hexa mesh. If more complex use tetras.
I suggest of course that you also create suitable boundary layer elements
as they are important especially when heat transfer is involved.

Regarding the solver have a look at
http://www.openfoam.com/features/standard-solvers.php

to decide which is the best solver to use (heat transfer)

Then go to the tutorials section of OpenFOAM installation and
study the corresponding tutorials of that solver.
See the settings specified in controlDict fvschemes fvsolutions etc

Let me know if you need help with ANSA.

Best regards,

Vangelis
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Old   March 12, 2011, 04:49
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Hi,

I still have read through the list of solvers, but can I use a solver from the group "Heat transfer and buoyancy-driven flows", if I have no buoyancy-driven flows?
I have a flow caused by a ventilator, thus forced convection (I suppose very turbulent)

Thanks for your answer.
If there are some more information and advices you or others want to tell me, please do so.

Regards,
Dirk
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Old   March 13, 2011, 07:37
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Hi,

does someone know a tutorial, which describes the procedure to put in the data from ANSA (geometry, boundary conditions,...) to ParaFoam?

Regards,
tH3f0rC3
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Old   March 14, 2011, 12:18
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Quote:
Originally Posted by tH3f0rC3 View Post
Hi,

does someone know a tutorial, which describes the procedure to put in the data from ANSA (geometry, boundary conditions,...) to ParaFoam?

Regards,
tH3f0rC3
I have found the pipe_bend Tutorial. It describes that procedure very good. Some of your collegues has suggested to do so in another thread.

But I have exported my data for a little test-modell and there was no blockmesh-file.
- So there's the question if ANSA made a mistake or ih ANSA does not create a blockmeshfile.
- Than it is my job to create his file. But I tried and it failed.

-> So my question if someone does know who made the mistake in this case. Was it me or was is ANSA? :-)

Regards,
tH3f0rC3
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Old   March 14, 2011, 15:38
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Vangelis Skaperdas
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Hi there

ANSA does not create a blockmesh file

It creates directly the complete polymesh folder that
contains all the information needed for the mesh
description (nodes, boundaries neighbours etc).
You do not need blockmesh.

Regards

Vangelis
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Old   March 14, 2011, 16:38
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Quote:
Originally Posted by vangelis View Post
Hi there

ANSA does not create a blockmesh file

It creates directly the complete polymesh folder that
contains all the information needed for the mesh
description (nodes, boundaries neighbours etc).
You do not need blockmesh.

Regards

Vangelis
Ok, these are exactly the files which where created inmy case, too.
But I think I have read in the OpenFoam User Guide, that OpenFoam needs a blockmesh-file.
But thanks for your answer, i will check tomorrow!

Regards,
tH3f0rC3
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Old   March 15, 2011, 02:17
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Vangelis Skaperdas
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The blockmesh file is only needed when there is no polymesh
folder and needs to be generated from the specs that are listed in blockmesh.
So blockmesh is the means to an end (the polymesh folder)
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Old   March 15, 2011, 03:30
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Ok.
When I blockMesh in the tutorials openFoam creates exactly the same files like ANSA outputs. So far so good.
But the fils created from ANSA seemed not to be exactly that what OpenFoam needs to solve them. I recognised that the files (faces.gz, neighbour.gz, owner.gz and points.gz( created from the blockMesh command have the ending .gz what the files created (exported) from ANSA do not have. This fils are shown as ANSA file.

So do I have to edit them, before OpenFoam can read them?
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Old   March 15, 2011, 05:43
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I can now specifie my problem:

The files exported from ANSA are not recognized as cpp-files and OpenFoam want files in cpp-format.

I think a problem could be that my ANSA can only export in OpenFoam versions 1.6 and not a higher version. But I'm working with version 1.7

Could this be the problem?
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Old   March 15, 2011, 06:24
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ok, no I have checked, that this isn't the mistake.
I will proceed on with checking.

The error message I recieve is the following:
__________________________________________________ ___________________________________
--> FOAM FATAL IO ERROR:
Unable to set reference cell for field p
Please supply either pRefCell or pRefPoint

file: /data/...MEIN VERZEICHNIS.../system/fvSolution::SIMPLE from line 73 to line 73
From function void Foam::setRefCell
(
const volScalarField&,
const volScalarField&,
label& scalar&,
bool
)
in file cfdTools/general/findRefCell/findRefCell.C at line 115
FOAM exiting __________________________________________________ ___________________________________
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