# Mesh area/volume calculations

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 March 14, 2016, 12:45 Mesh area/volume calculations #1 Senior Member     André Join Date: Mar 2016 Posts: 133 Rep Power: 9 Greetings, I am quite new to StarCCM and I am working with flow in porous media. One of the quantities of interest is the specific area (m2/m3) of the medium, and I was wondering if I could obtain this by dividing the total surface area of the mesh (which is already defined) by its occupied volume. In theory this should not be quite accurate since it will not compute the solid volume, only the fluid, but still I would like to know if this is possible and easy to do just to get an idea. Thanks in advance for any response! __________________ Sapere aude!

 March 15, 2016, 15:11 #2 Senior Member   Matt Join Date: Aug 2014 Posts: 931 Rep Power: 16 you should be able to setup reports and field functions to get this. Is it simply the face area / volume of the media?

March 15, 2016, 15:50
#3
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André
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Quote:
 Originally Posted by MBdonCFD you should be able to setup reports and field functions to get this. Is it simply the face area / volume of the media?

After some thought I'm thinking it should be not the total cell area, but only wall bounded surfaces (wall surface / total volume )

Possibly there should be some function to compute total wall area of a certain region...
__________________
Sapere aude!

March 15, 2016, 16:15
#4
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Matt
Join Date: Aug 2014
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This should be fairly straight forward...

1. Create a new sum report, title it A.
2. Assign Area: Magnitude as your scalar field function.
3. Assign region boundaries that make up your surface area. Make sure to select the interfaces where the porous region/fluid regions meet as well as any frames or walls that bound the outside. (See attachment).
4. Right click report A, select Run... and make sure the value makes sense.
5. Next, create a new sum report and title it V.
6. Assign volume as your scalar field function.
7. Assign your entire porous region as the input part.
8. Again, run the report and make sure the value makes sense.
9. Finally, create a new expression report and rename it specificA.
10. Assign dimensions of L=-1.
11. Define the function as \${AReport}/\${VReport}

You can then treat that report like any other... run it, create an annotation, etc...
Attached Images
 selections.png (159.7 KB, 81 views)

 March 16, 2016, 09:39 #5 Senior Member     André Join Date: Mar 2016 Posts: 133 Rep Power: 9 Thanks very much! Just one problem: The volume calculation should be pretty straight-forward, I'm using a cylinder as the boundary, so it's a simple calculation, however when I choose Parts -> Cylinder the computed volume is 0. Any suggestions? __________________ Sapere aude!

 March 16, 2016, 09:47 #6 Senior Member   Matt Join Date: Aug 2014 Posts: 931 Rep Power: 16 are you selecting the part or the region? that can make a difference. make sure you select region boundaries and not part surfaces

 March 16, 2016, 09:48 #7 Senior Member   Matt Join Date: Aug 2014 Posts: 931 Rep Power: 16 Sorry, not boundaries for volume. Just the region itself. Take a look at my attached image from earlier, it should illustrate the difference.

 Tags foam, mesh, porous, specific area