# Cell centroid and cell volume in general, and in Fluent

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 October 13, 2009, 19:07 Cell centroid and cell volume in general, and in Fluent #1 New Member   Zoltán Hercz Join Date: Sep 2009 Posts: 17 Rep Power: 15 Hi Is there anyone who can explain me how do the cell centroid(c_centroid) and cell volume(C_Volume) functions of Fluent work? What method they use to calculate the centroid and the volume of a cell. Im writing my code, and would like to create functions similar to these.Thanks.

 October 17, 2009, 11:09 #2 New Member   Emre Join Date: Oct 2009 Location: Ann Arbor, MI Posts: 12 Rep Power: 15 I don't how fluent does this but the following will work for arbitrary cell geometries: Code: ```Loop faces Loop face nodes Form a triangle using two subsequent face nodes and a point within the face (e.g average of face nodes) Calculate the resulting triangle area Add to face area Form a tetra using the triangle and a point within the cell volume Calculate tetra volume Add to cell volume Tetra centroid is known (google it) cell_centroid=cell_centroid+tetra_volume*tetra_centroid End face node loop End face loop cell_centroid=cell_centroid/cell_volume``` Hope this helps. __________________ Free CFD developer www.freecfd.com

 October 17, 2009, 11:55 #3 New Member   Zoltán Hercz Join Date: Sep 2009 Posts: 17 Rep Power: 15 Thank you for your answer. Since i asked i have already find an other method using the divergence theorem (Gauss) to transform volume integrals to surface integrals.

 October 17, 2009, 12:05 #4 New Member   Emre Join Date: Oct 2009 Location: Ann Arbor, MI Posts: 12 Rep Power: 15 Right, that will work too. I preferred the method I described since it will give the face areas, face centroids, cell volumes and cell centroids in one swipe. Good luck with your code. __________________ Free CFD developer www.freecfd.com