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Old   August 19, 2014, 04:06
Default Open Foam Tutorials
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Sachin
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I've been working through the tutorials and decided to attempt the motobike tutorial.

I have managed to generate the mesh using blockmesh, snappyHexMesh.

I still am unable to see the bike in paraFoam even after searching through the various threads. Someone mentioned reduce the xmin and ymax but I wasnt able to locate these options. Thoughts? Should I continue to suffer for a right of passage?

It appears that this tutorial contains boundary conditions so I assumed I could run icoFoam or simpleFoam to obtain a solution. Is this correct.

In attempt to run icoFoam and simpleFoam it closes by saying the following:

Create time

Create mesh for time = 3

Reading transportProperties

Reading field p



--> FOAM FATAL IO ERROR:
cannot open file

file: /home/adam/OpenFOAM/OpenFOAM-1.6.x/tutorials/incompressible/simpleFoam/motorBike/3/p at line 0.

From function regIOobject::readStream()
in file db/regIOobject/regIOobjectRead.C at line 62.

FOAM exiting

I looked at the "3" folder which I believe is the final mesh folder and was not able to locate "p at line 0"
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Old   August 19, 2014, 10:15
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well, i guess you are in wrong place
if i understood you correctly, you are going to run icoFoam, so this solver needs file p, as there is no file p (pressure file) in that folder, it exits
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Old   August 19, 2014, 17:47
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snappyHexMesh - if not specified with the -overwrite parameter - generates 3 time directories in your case folder. You have to access the last time with paraview, in order to see the motorbike. You can simply click on the play icons in to top right corner.

A nice option is to use the -overwrite option, which writes the mesh into constant/polyMesh, rathan <time>/polyMesh. Then you can execute the solver right away.
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Old   August 19, 2014, 18:26
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Sachin m

to view the mesh in paraFoam you have to remove the selection of volumefields because they are not yet there. To run the case you need to copy the 0 directory files of p, U etc to the last time dir and than you can start the simulation from there. Beter is to copy the mesh to the constant dir and remove all time directories except 0.

Hope this helps
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Old   August 20, 2014, 08:28
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Thanks everyone for ur replies. I ll run it and let you knw the results.
In between I was trying with the wigley hull tutorials. I was able to run on LTSInterFoam. But iam unable to view the results on paraview.
I had changed the file name of alpha1.org to alpha1 to run the simulation.
In paraview,when i tried to switch on the volume meshes, the program closes with a warning :


~/OpenFOAM/ubuntu-2.1.0/run/wigleyHull(1604) paraFoam
created temporary 'wigleyHull.OpenFOAM'
--> FOAM Warning :
From function polyMesh::readUpdateState polyMesh::readUpdate()
in file meshes/polyMesh/polyMeshIO.C at line 204
Number of patches has changed. This may have unexpected consequences. Proceed with care.


--> FOAM FATAL IO ERROR:
size 12000 is not equal to the given value of 182759

file: /home/ubuntu/OpenFOAM/ubuntu-2.1.0/run/wigleyHull/200/U from line 18 to line 13248.

From function Field<Type>::Field(const word& keyword, const dictionary&, const label)
in file lnInclude/Field.C at line 236.

FOAM exiting

Segmentation fault (core dumped)
~/OpenFOAM/ubuntu-2.1.0/run/wigleyHull(1605)


what could be the possible reason.
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Old   August 20, 2014, 09:33
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Read the error messages, they usually tell you what went wrong. In this case, the U field in the 200 directory does not have the same length (cell numbers) as the polyMesh. This usually happens when you don't clean up your case properly, before rerunning it.
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Old   August 21, 2014, 02:42
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thanks everyone. I have successfully run the wigley hull tutorial and was able to view the pressure contour. But the results seems a little weird. May b because I am not much used with paraview.
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Old   August 21, 2014, 02:52
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Can anyone tell me where in the code does we specify the free surface parameters
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Old   August 21, 2014, 03:21
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How can I get the drag value on the hull?
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Old   August 21, 2014, 03:26
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Just google it. Drag can be computed via the forces function object and the free surface can be visualized by a contour at alpha=0.5
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Old   August 22, 2014, 01:09
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I meant how do we specify a particular free surface plane for a particular case?
Free surface can be different for different cases. Where do we specify the free surface in a case?
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Old   August 22, 2014, 05:00
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You mean how to initialize the free surface? Use setFields or funkySetFields and have a look into the multiphase tutorials. That is explained there (well, not explained, but shown) in a sufficient manner.

Spoiler: You don't actually specify the free surface itself, but the volume fraction alpha1.
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Old   August 22, 2014, 06:04
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yup...I see:

defaultFieldValues
(
volScalarFieldValue alpha1 0
);

regions
(
boxToCell
{
box (-100 -100 -100) (100 100 0);
fieldValues
(
volScalarFieldValue alpha1 1
);
}
);



Can you explain this to me please.??
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Old   August 22, 2014, 06:10
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Just try google to find something on "OpenFOAM" and "setFields", it's not too hard. First hit: Open Foam /Setfields
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Old   August 26, 2014, 01:13
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Have anyone tried the wigley hull tutorial with a customized hull and succeeded in running the program?
If so please help me out with the steps to be carried out
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Old   August 26, 2014, 04:07
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can anyone tell me how to install netgen on linux
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Old   August 27, 2014, 03:54
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Iam working on a customized hull.when i used snappyhexmesh, i got the following error message:

/ubuntu-2.1.0/run/wigleyHull(2008) paraFoam
created temporary 'wigleyHull.OpenFOAM'
~/OpenFOAM/ubuntu-2.1.0/run/wigleyHull(2009) snappyHexMesh -overwrite
/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.1.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 2.1.0-0bc225064152
Exec : snappyHexMesh -overwrite
Date : Aug 27 2014
Time : 17:31:26
Host : "ubuntu"
PID : 5226
Case : /home/ubuntu/OpenFOAM/ubuntu-2.1.0/run/wigleyHull
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Disallowing user-supplied system call operations

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

Create mesh for time = 0

Read mesh in = 0.07 s

Overall mesh bounding box : (-10750 -5750 -5500) (20250 5750 5539.9)
Relative tolerance : 1e-06
Absolute matching distance : 0.0348587

word::stripInvalid() called for word ��~?�-����ҽ��i?t�D�ȒD+�Z?�ίD��D�cU?��D3k�D
For debug level (= 2) > 1 this is considered fatal
Aborted (core dumped)
~/OpenFOAM/ubuntu-2.1.0/run/wigleyHull(2010)



Can anyone tell me what the problem could be?

I had to scale the geometry using convert to meter and the value was 1000.
The hull was modelled in Free ship and was imported to solidworks and was then converted to stl format, since the stl file generated from the freeship was just a half part of the symmetric body.
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Old   August 27, 2014, 18:05
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hello,

I am no expert, but I think that your STL file is binairy and should be ascii.

hope this helps
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Old   August 28, 2014, 00:25
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Thats true wouter, the problem was with the geometry file.
the stl file imported from solidworks has got some problems.
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Old   August 29, 2014, 02:08
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I tried a wigley hull tutorial with my own hull. But when i ran snappy HexMesh, icould only see the ship meshed, the outside domain just disappeared.

what could be the posible reason?
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