drag coefficient of a cylinder using GUI

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Birro
Posts: 5
Joined: Fri Jan 06, 2017 2:16 pm

drag coefficient of a cylinder using GUI

Post by Birro »

Hello everybody

I'm a quite new using CS and I'm trying to calculate the Drag coefficient of a cylinder. I've found a manner in the CS documentation using Fortran subroutines. Can I calculate it directly from CS GUI?

Kind regards,

Thiago Vasconcellos Birro
Yvan Fournier
Posts: 4070
Joined: Mon Feb 20, 2012 3:25 pm

Re: drag coefficient of a cylinder using GUI

Post by Yvan Fournier »

Hello,

To directly compute the drag coefficient, you'll need user subroutines.

With the GUI, you can activate computation and postprocessing output of boundary stresses, possibly output on a mesh subset, which you could then use to compute the drag coefficient using a postprocessing tool.

Regards,

Yvan
Birro
Posts: 5
Joined: Fri Jan 06, 2017 2:16 pm

Re: drag coefficient of a cylinder using GUI

Post by Birro »

Hello Yvan

Thanks for replying. I'm looking for information about using the Paraview to calculate the drag coefficient. However, Is there some way to only separate the cylinder surface to integrate on it?

Kind regards,

Birro
Yvan Fournier
Posts: 4070
Joined: Mon Feb 20, 2012 3:25 pm

Re: drag coefficient of a cylinder using GUI

Post by Yvan Fournier »

Hello,

Yes, you can create a specific postprocessing surface mesh. Under "Calculation Control/Ouput Control" in the GUI using the same selection criteria (i.e. group name) you would use to define the wall boundary condition on the cylinder (assuming you have a specific group for that area).
Using the "separate blocks" filter under ParaView, you can then load just this part, so the integration filters should then be enough to compute the forces you need.

Regards,

Yvan
Birro
Posts: 5
Joined: Fri Jan 06, 2017 2:16 pm

Re: drag coefficient of a cylinder using GUI

Post by Birro »

Hello Yvan
So, I'm testing the advices that you gave me. However, a strange thing happened. I've created the group CYLIN, meaning the internal surface of the Cylinder. So, when I configured CYLIN as an internal surface, the CS produced an error: "SIGSEGV signal (forbidden memory area access) intercepted!" The same group was identified correctly by the preprocessor.log.

Kind Regards
Last edited by Birro on Thu Jan 12, 2017 1:48 pm, edited 1 time in total.
Birro
Posts: 5
Joined: Fri Jan 06, 2017 2:16 pm

Re: drag coefficient of a cylinder using GUI

Post by Birro »

I'm also sending the files

best regards
Attachments
preprocessor.log
(5.38 KiB) Downloaded 285 times
listing.txt
(63.66 KiB) Downloaded 319 times
setup.log
(19.27 KiB) Downloaded 291 times
Yvan Fournier
Posts: 4070
Joined: Mon Feb 20, 2012 3:25 pm

Re: drag coefficient of a cylinder using GUI

Post by Yvan Fournier »

Hello,

Could you also post your xml file (and mesh if it is not too large) ?

Best regards,

Yvan
Birro
Posts: 5
Joined: Fri Jan 06, 2017 2:16 pm

Re: drag coefficient of a cylinder using GUI

Post by Birro »

Hello everybody

I've had a trouble to send the mesh and the xml here, so I'm sending by a link. For the simulations, I'm using the CS 4.0.6.

https://www.dropbox.com/sh/bc8igqdkgw7o ... bpoca?dl=0


Kind regards

Thiago Birro
Yvan Fournier
Posts: 4070
Joined: Mon Feb 20, 2012 3:25 pm

Re: drag coefficient of a cylinder using GUI

Post by Yvan Fournier »

Hello,

I fixed the crash, which was related to insufficient checks on the input.

You also need to fix your setup, which will avoid the issue even with the version you have:
the postprocessing output mesh for the cylinder can be named whatever you want, but you need to define it as a mesh of boundary cells, and use CYLIN as a selection criteria.

Regards,

Yvan
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