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
Posts: 1416
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

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
after_enabling_all_options_in report_view.JPG (203.29 KiB) Viewed 758 times
thschrader
Posts: 1416
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

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)
User avatar
oliveroxtoby
Posts: 316
Joined: Fri Dec 23, 2016 9:43 am
Location: South Africa

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?
Please provide all the information requested in this post before reporting problems with CfdOF.
thschrader
Posts: 1416
Joined: Sat May 20, 2017 12:06 pm
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!
allright.JPG
allright.JPG (148.31 KiB) Viewed 712 times
allright2.JPG
allright2.JPG (86.24 KiB) Viewed 712 times
thschrader
Posts: 1416
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

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
one_model.JPG (37.08 KiB) Viewed 695 times
User avatar
Kunda1
Posts: 5480
Joined: Thu Jan 05, 2017 9:03 pm

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
Posts: 1416
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

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...
thschrader
Posts: 1416
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

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
User avatar
oliveroxtoby
Posts: 316
Joined: Fri Dec 23, 2016 9:43 am
Location: South Africa

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
Please provide all the information requested in this post before reporting problems with CfdOF.
User avatar
bernd
Posts: 8329
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

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