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HELP!!! viewFactorsGen is not calculating view factors!!

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Old   September 15, 2014, 09:55
Default HELP!!! viewFactorsGen is not calculating view factors!!
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Alex
Join Date: Oct 2013
Posts: 337
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zfaraday will become famous soon enough
Hi all,

I have been trying for a few days to set up a case where a cylindrical heater heats up, by radiation mainly, a domain composed by air and a couple of shields that surround the heater. The geometry is shown in the pictures. Both, heater and shields, have been generated by createBaffles utility (thermal baffles).

Everything works fine but the generation of the view factors that shows up an error I cannot understand. This is the viewFactorsGen log-file:

Code:
/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.3.x                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : 2.3.x-d406bd3aab60
Exec   : viewFactorsGen
Date   : Sep 15 2014
Time   : 11:48:31
Host   : "linux-cfd"
PID    : 2581
Case   : /home/cfd/OpenFOAM/cfd-2.3.x/run/PFC/Proves/cylinder/cylindricalMesh.3.1_testing_view_factors_1region
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Allowing user-supplied system call operations

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

Create mesh for time = 0


Creating single cell mesh...

Created single cell mesh...

Total number of coarse faces: 114

View factor patches included in the calculation : 9(0 1 2 3 4 5 6 7 8)
Dumping rays to "/home/cfd/OpenFOAM/cfd-2.3.x/run/PFC/Proves/cylinder/cylindricalMesh.3.1_testing_view_factors_1region/allVisibleFaces.obj"
cmd:"objToVTK /home/cfd/OpenFOAM/cfd-2.3.x/run/PFC/Proves/cylinder/cylindricalMesh.3.1_testing_view_factors_1region/allVisibleFaces.obj /home/cfd/OpenFOAM/cfd-2.3.x/run/PFC/Proves/cylinder/cylindricalMesh.3.1_testing_view_factors_1region/allVisibleFaces.vtk"
/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.3.x                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : 2.3.x-d406bd3aab60
Exec   : objToVTK /home/cfd/OpenFOAM/cfd-2.3.x/run/PFC/Proves/cylinder/cylindricalMesh.3.1_testing_view_factors_1region/allVisibleFaces.obj /home/cfd/OpenFOAM/cfd-2.3.x/run/PFC/Proves/cylinder/cylindricalMesh.3.1_testing_view_factors_1region/allVisibleFaces.vtk
Date   : Sep 15 2014
Time   : 11:48:31
Host   : "linux-cfd"
PID    : 2586
Case   : /home/cfd/OpenFOAM/cfd-2.3.x/run/PFC/Proves/cylinder/cylindricalMesh.3.1_testing_view_factors_1region
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
End


Calculating view factors...
#0  Foam::error::printStack(Foam::Ostream&) at ??:?
#1  Foam::sigFpe::sigHandler(int) at ??:?
#2   in "/lib64/libc.so.6"
#3  
 at ??:?
#4  
 at ??:?
#5  __libc_start_main in "/lib64/libc.so.6"
#6  
 at /home/abuild/rpmbuild/BUILD/glibc-2.17/csu/../sysdeps/x86_64/start.S:126
This sort of error is kind of meaningless to me, it seems like a floating point exception due to the sigFpe shown in the message, which is usually related to a division by zero as far as I know (if I'm wrong, correct me please). However, I don't have any clue on what is causing the error since I don't know what the viewFactorsGen utility is exactly doing (I have taken a look into the code of it, but I'm not much skilled with C++ so I couldn't find any hint in there). I have attached the "constant/viewFactorsDict" file so that you can take a look at my specification. However, I have tried a lot of combinations in this file so I think it's not a matter of viewFactorsDict definition. I also thought that maybe the problem was the geometry used in both baffles (perhaps OpenFOAM can't handle cylindrical geometry in a baffle creation?).

I hope that someone can help me with this case with the information I provided (if more information is needed feel free to ask), because I have been struggling with this case for a while. Any comment or hint will be much welcome.

Thanks in advance.


Alex
Attached Images
File Type: jpg 1.jpg (12.4 KB, 50 views)
File Type: jpg 2.jpg (11.2 KB, 54 views)
Attached Files
File Type: txt log.viewFactorsGen.txt (3.3 KB, 14 views)
File Type: txt viewFactorsDict.txt (1.8 KB, 46 views)
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The case I talk about in this site was solved with chtMultiRegionSimpleFoam solver and involves radiation. Some basic tutorials are also resolved step by step in the web. If you are interested in these matters, you are invited to come in!
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