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-   -   Forces and moments calculation with .VTU volume file file (https://www.cfd-online.com/Forums/su2/250497-forces-moments-calculation-vtu-volume-file-file.html)

abhijithmoni June 20, 2023 01:54

Forces and moments calculation with .VTU volume file file
 
I'm trying to calculate forces and moments over a wing surface. SU2 is writing a .VTU file but there are no boundary zones or surfaces to integrate and find the forces and moments. Is there a workaround to split the volume zone as boundaries to perform the required calculation. Please help me with this.


Thanks
Abhijith

giovanni.medici June 20, 2023 03:56

Quote:

Originally Posted by abhijithmoni (Post 852080)
I'm trying to calculate forces and moments over a wing surface. SU2 is writing a .VTU file but there are no boundary zones or surfaces to integrate and find the forces and moments. Is there a workaround to split the volume zone as boundaries to perform the required calculation. Please help me with this.


Thanks
Abhijith

Dear Abhijith,

SU2 outputs two *.VTU (s), one for the volume and one for the surface

Quoting directly the tutorials : https://su2code.github.io/tutorials/Inviscid_Bump/


Quote:

Any boundary markers that are listed in the MARKER_PLOTTING option will be written into the surface solution vizualization file.
I hope it helps. I think there are also other options, like force-breakdown, don't know whether they are still supported

https://www.cfd-online.com/Forums/su...down-file.html

For sure I used that feature in the past.

It was something like adding to your cfg file the following:

Code:

BREAKDOWN_FILENAME= forces_breakdown.txt
WRT_FORCES_BREAKDOWN = YES


bigfootedrockmidget June 20, 2023 03:58

Hi,
Just rerun it with 1 iteration and write a PARAVIEW_MULTIBLOCK instead of a regular PARAVIEW.
You can also get the coefficients directly in SU2.

Just add AERO_COEFF to HISTORY_OUTPUT
The coefficients are computed over the surfaces in MARKER_MONITORING
using REF_LENGTH, REF_AREA and REF_ORIGIN_MOMENT_X (and _Y and _Z)

abhijithmoni June 21, 2023 09:13

3 Attachment(s)
Dear Giovanni (@giovanni.medici) and @bigfootedrockmidget,

Thanks for both of your inputs. I did the following changes
Code:

OUTPUT_FILES = (PARAVIEW)
to

Code:

OUTPUT_FILES = (PARAVIEW_MULTIBLOCK)
But the output was just a .vtm file without any data written in it. I have attached images with the configuration file for your reference.

Ideally, I require the volume file (eg. flow.vtu) with the boundary zone to do some postprocessing, I managed to get the surface_flow file already.

Please help me fix the error.

Many thanks. I really appreciate the your time and inputs.

Best
Abhijith

bigfootedrockmidget June 21, 2023 17:26

What is the content of the vtm file? It is a plain text file and it should contain the names of the vtu files, and the vtu files should have been written to a separate folder.

bigfootedrockmidget June 21, 2023 17:57

...and the vtm file can be loaded in paraview and you will have all information available. You can then use 'extract block' to select specific mesh elements like the interior or a boundary.

abhijithmoni June 23, 2023 01:45

3 Attachment(s)
@bigfootedrockmidget thanks for your reply and input. I'm attaching the .vtm file for your reference. There was an error in opening the .vtm file because it is looking for the following files: WING.vtu, FARFIELD.vtu and SYMMETRY.vtu. Even though I have them on both MARKER_PLOTTING= (WING, FARFIELD, SYMMETRY ) and MARKER_MONITORING= (WING, FARFIELD, SYMMETRY). I end up only getting a surface_flow.vtu file as an output.

bigfootedrockmidget June 23, 2023 15:11

Is your vtm file named flow.vtm? Does su2 create a folder called flow that contains the vtu files?

abhijithmoni June 24, 2023 00:32

No, SU2 does not create any folder. The file is named just ".vtm". The files shown in the attached image in my previous reply are the only contents inside the working directory.

SU2 Version: Release 7.5.0 "Blackbird"

bigfootedrockmidget June 24, 2023 03:43

Your config file works for me with the latest develop version. What operating system are you running on? And did you compile the code yourself or did you use one of the prebuilt executables?

It looks like in your case, su2 does not have any prefix for the filename so your filename is .vtm. And since the prefix is used to create the folder, it cannot write the folder.

abhijithmoni June 24, 2023 08:14

Quote:

Originally Posted by bigfootedrockmidget (Post 852295)
Your config file works for me with the latest develop version. What operating system are you running on? And did you compile the code yourself or did you use one of the prebuilt executables?

It looks like in your case, su2 does not have any prefix for the filename so your filename is .vtm. And since the prefix is used to create the folder, it cannot write the folder.

I'm on Windows OS, I'm using the prebuilt executable SU2_CFD.exe.

I have also tried the latest version of SU2 with full administrative previlage but it works the same way.

Is there a way to add a file name to .vtm ?


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