# Bugs in fvcsurfaceIntegrate

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 January 5, 2009, 08:01 Dear foamers what is t #1 Senior Member     su junwei Join Date: Mar 2009 Location: Xi'an China Posts: 151 Rep Power: 20 Dear foamers what is the difference between fvc::surfaceIntegrate and fvc::surfaceSum? Isn't it an additional division of volume in fvc::surfaceIntegrate ? I have just noticed that they are different when suming the surface field In fvc::surfaceIntegrate, it is forAll(owner, facei) { ivf[owner[facei]] += issf[facei]; ivf[neighbour[facei]] -= issf[facei]; } while in fvc::surfaceSum, it is forAll(owner, facei) { ivf[owner[facei]] += issf[facei]; ivf[neighbour[facei]] += issf[facei]; } Why they are different when dealing with neighbour cell for the current face? Is it a bug for fvc::surfaceIntegrate? Junwei

 January 5, 2009, 08:45 "surfaceIntegrate" forms the b #2 Senior Member   Join Date: Mar 2009 Posts: 854 Rep Power: 22 "surfaceIntegrate" forms the basis of the Gauss integrals for evaluating explicit derivatives, see e.g. fvc::div. The reason there is a change of sign is that the face-areas are outward-pointing from the "owner" and hence inward-pointing to the "neighbour". This is assuming what is being "summed" is some kind of flux, i.e. something multiplied or dotted with the cell face areas. "surfaceSum" is simply that, a sum of a surface field over the cell-faces which is needed for some forms of averaging. H makaveli_lcf and scleakey like this.

 July 29, 2010, 11:09 fvc :: reconstruc #3 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,266 Blog Entries: 1 Rep Power: 24 hi dear friend what dose "fvc :: reconstruct" do exactly ? i have a "surfaceScalarField" and i want to change it to a "volumeScalarField", what can i do ? can i use fvc :: reconstruct ? whats its effect on data?

 June 25, 2013, 13:10 #4 Senior Member   Anne Gerdes Join Date: Aug 2010 Location: Hamburg Posts: 168 Rep Power: 15 The surfaceIntegrate utility sounds very useful to me. Is it possible to apply this for a face-based source term inside the UEqn()? For which objects can we use this method? When applying this to velocity U I obtain an error message. Thank you for an answer in advance. Kind Regards Anne Lincke

 July 7, 2013, 10:29 #5 Retired Super Moderator   Bruno Santos Join Date: Mar 2009 Location: Lisbon, Portugal Posts: 10,975 Blog Entries: 45 Rep Power: 128 Greetings Anne, It would help if you provided more information about the problem at hand. I can only guess that the following might help you understand better how OpenFOAM's "reconstruct" and "interpolate" work: https://github.com/wyldckat/reconstr...te-fields/wiki Best regards, Bruno makaveli_lcf likes this. __________________ OpenFOAM: FAQ | Getting started Forum: How to get help, to post code/output and forum guide Read this before sending me PM