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Extraction and Manipulation of div(U) Rank 1/2 Tensor (volTensorField)

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Old   September 11, 2013, 23:56
Default Extraction and Manipulation of div(U) Rank 1/2 Tensor (volTensorField)
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JFM
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John Anonymous
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Good day everyone

I am using OpenFOAM to assess a hydraulic structure which is designed to operate at critical condition (Fr=1). Previously I had assessed this structure using two commercial 2D FVM model, however the results were not acceptable.

As a result I have created a 3D interFoam model of the structure and are aiming to prove that OpenFOAM is a suitable tool for designers. I need to determine the influence, if any, of the cross momentum terms from the convective velocity field, div (phi, U). The terms I am particularly interested in are:
x-direction: u.du/dx + v.du/dy + w.du/dz
y-direction: etc
z-direction: etc
(at this stage I am not interested in the RAS or LES stresses)

It appears that these components are indeed calculated and are stored as a tensor (volTensorField) with a NOWRITE command. However, I cannot find anyway (in the forum or other references) to write this tensor out from the model. Could someone provide some direction on how this could be achieved, please include file / dictionary names that may need to be amended.

I have been using OpenFOAM for around a year but still have limited confidence when it comes to manipulation of files therefore any assistance will be greatly appreciated - hopefully I can return the favour one day.

Regards
JFM

Last edited by JFM; September 11, 2013 at 23:59. Reason: additional details on 2D modelling
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Old   September 12, 2013, 01:54
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Bernhard
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As far as I know, you can force the writing of a field by

Code:
tensorName.write();
During run-time, you might only want to write it at the specific output time-steps, than you need something like

Code:
if (mesh.time().outputTime())
{
    tensorName.write();
}
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Old   September 13, 2013, 20:26
Default Files to amend
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John Anonymous
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Thank you Bernhard

Which source files create the interFoam div tensor and which files need to be amended . Or perhaps someone could provide a link to some references that may provide some guidance on tensors creation, storage and manipulation.

Kind regards
John
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