# Bugs in fvcsurfaceIntegrate

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 January 5, 2009, 09:01 Dear foamers what is t #1 Senior Member     su junwei Join Date: Mar 2009 Location: Xi'an China Posts: 151 Rep Power: 10 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, 09:45 "surfaceIntegrate" forms the b #2 Senior Member   Join Date: Mar 2009 Posts: 854 Rep Power: 13 "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

 July 29, 2010, 11:09 fvc :: reconstruc #3 Senior Member   Nima Sam Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,132 Blog Entries: 1 Rep Power: 15 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: 152 Rep Power: 7 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 Super Moderator   Bruno Santos Join Date: Mar 2009 Location: Lisbon, Portugal Posts: 8,659 Blog Entries: 34 Rep Power: 87 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 __________________ OpenFOAM: Frequently Asked Questions | Useful links for building and using Forum: How to ask for help | Posting code and output with [CODE] My to-do list and when I'll be able to come to the forum: http://wyldckat.github.io And please: Read this before sending private messages to me

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