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-   -   Surface intgrals (http://www.cfd-online.com/Forums/openfoam-pre-processing/62175-surface-intgrals.html)

anja May 3, 2006 13:09

Hi all, can someone please
 
Hi all,

can someone please explain me, how I can get the size of one cell/face within a patch?

I'm trying to write an application for surface integrals.

Thanks
Anja

theof May 4, 2006 02:48

Hi Anja, I have written a mod
 
Hi Anja,
I have written a module for paraview that allows surface integrals for flow rate computations, torque, energy losses, etc.
Into your own compiled paraview, it can be easily added as an extra external module.
Is that what you need? Let me know if you are interested and I'll make it available.
thf

anja May 8, 2006 10:00

Hi, for the moment I'm just t
 
Hi,
for the moment I'm just trying to get surface integrals for the pressure, meaning calculating an average for an inlet.

Any suggestions for that?

Anja

atzaru May 9, 2006 03:45

Hi Theophane Foggia, I woul
 
Hi Theophane Foggia,

I would be very interested in the module you have written.

and if is possible a brief description of how this can be integrated with paraview.

thanks a lot
atzaru

eugene May 9, 2006 05:32

Simply averaging the pressure
 
Simply averaging the pressure values would be a very bad idea, i.e.

p_average != average(p);

Rather

p_average should be volume or surface weighted.

For a known patch ID: patchID

scalar patchPmean = gSum(p.boundaryField()[patchID] * mesh.boundary()[patchID].magSf())/gSum(mesh.boundary()[patchID].magSf());

Using gSum instead of sum allows the expression to work in parallel as well.

anja May 9, 2006 06:13

But in the programmers guide (
 
But in the programmers guide (chapter 2.4.10) it's saying that the function average "produces an area weighted average".
But when I tried, it did not work.

theof May 15, 2006 05:11

Hi The filter I mentioned abo
 
Hi
The filter I mentioned above is available here as an extra external module for paraview:

http://public.kitware.com/pipermail/paraview/attachments/20060322/cf8b2475/vtkCS CSIntegrateVariables.tar.bin

In paraview-2.4.3 the integrate attribute filter will work as well for 2D integration. It is much more advanced stuff but less easy to get through.

melanie August 3, 2006 11:30

Hi Theophane, could you pleas
 
Hi Theophane,
could you please give me hint to install this module as I never worked with CMake and I'm using paraFoam ?
Thanks !
melanie

theof August 4, 2006 01:43

Hi Melanie, I think you shoul
 
Hi Melanie,
I think you should first try to use the Integrate Attributes filter in ParaView. It is available in paraview 2.4.* and above. If you really want to install the Integrate Variables filter, the README should tell what to do.
Theophane

melanie August 4, 2006 06:26

Thanks Theophane, I tried thi
 
Thanks Theophane,
I tried this morning the Integrate Attributes, but I cannot find a guide to understand how it works... I am not able to select the surface I want the attribute be calculated on !

theof August 4, 2006 06:54

Well it works like any other p
 
Well it works like any other paraview filter, it should select automatically the surface you want to integrate on. Make sure the surface is highlighted in the selection window before applying the Integrate Attributes filter.

melanie August 4, 2006 07:20

ok, now I've understood! I hav
 
ok, now I've understood! I have to create a cut and apply the filter on it.
meanwhile I have another question: for me it does not work if I create a cut exactly located on a boundary, because there are no attributes on the created cut ? is there a reason for this ?
thank you


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