Computational Fluid Dynamics (CFD) workbench using OpenFOAM

A subforum specific to the development of the OpenFoam-based workbenches ( Cfd https://github.com/qingfengxia/Cfd and CfdOF https://github.com/jaheyns/CfdOF )

Moderator: oliveroxtoby

thschrader
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Postby thschrader » Thu Jan 18, 2018 3:39 pm

oliveroxtoby wrote:
Thu Jan 18, 2018 3:00 pm
Can you confirm that if you right-click in the report view and go to options, everything is checked, then re-run the macro please?
Enabled all options in report view, restart FC, open macro, execute:
(@Kunda1: I will try the newest FC0.17, need time to check the FEM/CFD-Preferences)
after_enabling_all_options_in report_view.JPG
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Postby thschrader » Thu Jan 18, 2018 4:38 pm

Kunda1 wrote:
Thu Jan 18, 2018 2:55 pm
thschrader wrote:
Thu Jan 18, 2018 10:38 am
Version: 0.17.12940 (Git)
Perhaps update to latest HEAD (0.17.13050) and retest?
Did the procederes above with the newest dev-snapshot.
No difference when using
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13042 (Git)
Build type: Release
Branch: master
Hash: 9a215440b8a0140dbc2e8778e66cf63feeac7114
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.1.0
Locale: German/Germany (de_DE)
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oliveroxtoby
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Postby oliveroxtoby » Fri Jan 19, 2018 7:08 am

thschrader wrote:
Thu Jan 18, 2018 4:38 pm
Did the procederes above with the newest dev-snapshot.
No difference when using
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13042 (Git)
Build type: Release
Branch: master
Hash: 9a215440b8a0140dbc2e8778e66cf63feeac7114
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.1.0
Locale: German/Germany (de_DE)
Hi Thomas

Firstly, thanks for all the testing - much appreciated. This is very strange - no idea why it does not give an issue on my system. Perhaps your observation about the solid is a clue. On other geometries I have found the boolean shape splitting operations to be more robust than the 'Cut' operation, so I have modified the macros to use the boolean XOR instead of Cut. If you are willing could you check if this fixes the problem on your system?
thschrader
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Location: Germany

Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Postby thschrader » Fri Jan 19, 2018 9:56 am

oliveroxtoby wrote:
Fri Jan 19, 2018 7:08 am
... so I have modified the macros to use the boolean XOR instead of Cut.
:) :) :) Cheers!
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Postby thschrader » Fri Jan 19, 2018 12:55 pm

@Oliver
I completele deleted FC0.17 (including the config-files) from my pc
and did a new installation. Now I get ONE body when importing the step.
The same happens with the original file from grabcad. I have absolutely no
idea what the reason could be... :o
one_model.JPG
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Kunda1
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Postby Kunda1 » Fri Jan 19, 2018 3:54 pm

Want to contribute back to FC? Checkout:
#lowhangingfruit | Use the Source, Luke. | How to Help FreeCAD | How to report FC bugs and features
thschrader
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Postby thschrader » Fri Jan 19, 2018 4:54 pm

Kunda1 wrote:
Fri Jan 19, 2018 3:54 pm
Splash screen anyone?
With a transient simulation (calculation-time!) instead of a steady state we could produce
an animated splashsreen.
But:
The falcon was not designed with FC. The model was taken from grabcad:
https://grabcad.com/library/millennium- ... -version-1
I dont know if this would be correct...
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Postby thschrader » Sat Jan 20, 2018 10:13 am

Hello Oliver,
I have a general question about cfd-simulations.
Is it always necessary to switch on the turbulence option?
For instance, when I scale up the falcon to its "original" dimension (length approx 34 m)
and use a speed of 300 km/h (when Han Solo approaches the landing zone :) ), you get
a Re-number of approx 1,4E8. The gravitationally-forces of the fluid are dominating and
I would skip the turbulence. Is that right?
How do you estimate the k-omega-values? With a turbulence calculator? Which one?
regards Thomas
http://ichrome.com/blogs/archives/342
https://www.cfd-online.com/Tools/turbulence.php
https://www.learncax.com/knowledge-base ... t-boundary
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oliveroxtoby
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Postby oliveroxtoby » Tue Jan 23, 2018 7:15 am

thschrader wrote:
Sat Jan 20, 2018 10:13 am
Hello Oliver,
I have a general question about cfd-simulations.
Is it always necessary to switch on the turbulence option?
For instance, when I scale up the falcon to its "original" dimension (length approx 34 m)
and use a speed of 300 km/h (when Han Solo approaches the landing zone :) ), you get
a Re-number of approx 1,4E8. The gravitationally-forces of the fluid are dominating and
I would skip the turbulence. Is that right?
Generally only for laminar flow where Re < O(1e3) is it justified to ignore the turbulence.
thschrader wrote:
Sat Jan 20, 2018 10:13 am
How do you estimate the k-omega-values? With a turbulence calculator? Which one?
regards Thomas
http://ichrome.com/blogs/archives/342
https://www.cfd-online.com/Tools/turbulence.php
https://www.learncax.com/knowledge-base ... t-boundary
There are some guidelines for the far field values in https://turbmodels.larc.nasa.gov/sst.html
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Re: Computational Fluid Dynamics (CFD) workbench using OpenFOAM

Postby bernd » Wed Jan 24, 2018 6:16 am

bernd wrote:
Mon Jan 15, 2018 4:53 pm
@thomas, FYI
some time ago we had a problem with to much entries in a fixed contraint. Werner fixed the problem and we could have more than 3000 faces as reference shapes. I added them by python.
here some code to add all faces of a shape as reference shapes to an FEM object: https://forum.freecadweb.org/viewtopic. ... 10#p211310