# Point BCs for Heat Transfer Problem

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 May 30, 2013, 20:19 Point BCs for Heat Transfer Problem #1 Member   Join Date: May 2013 Location: Canada Posts: 32 Rep Power: 5 I'm attempting to run a simple 2-D conduction simulation but I'm either too inexperienced or straying into forbidden territory in my simulation setup. I want to create a pentagonal array of point-temperature boundary conditions on an adiabatic-walled cylinder with air as the internal fluid (no flow), and let the simulation find the final steady-state distribution. In other words, have 5 temperature points every 72-degrees around the cylinder. My problem is that I can't find any information on creating point BCs. Does anyone have any advice on how to create such a system with blockMesh, if possible? I'd appreciate any help, as my searches have led me no where.

 May 31, 2013, 03:17 #2 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,193 Blog Entries: 1 Rep Power: 16 dear body please read this post, then post enough information here, then forum users will help you __________________ Telegram channel (https://telegram.me/openfoam4Iranian) My Weblog (http://openfoam.blogfa.com/) Training Course on OpenFOAM at (http://www.isme.ir/)

 May 31, 2013, 12:05 #3 Member   Join Date: May 2013 Location: Canada Posts: 32 Rep Power: 5 Well, there's not much more I can clarify since I'm looking for help setting up the problem in blockMesh. I'm using OF 2.1.X. I don't have case files or a mesh since that's what I'm seeking help with initialising. What further information can I provide that might be of any more use than my initial post? I made a cylinder in blockMesh from a rectangular prism: Code: ```vertices ( ( 63.5 -63.5 0.0) //0 ( 63.5 63.5 0.0) ( -63.5 63.5 0.0) ( -63.5 -63.5 0.0) ( 63.5 -63.5 1.0) //4 ( 63.5 63.5 1.0) ( -63.5 63.5 1.0) ( -63.5 -63.5 1.0) ); blocks ( hex (0 1 2 3 4 5 6 7) (10 10 1) simpleGrading (1 1 1) ); edges ( arc 2 1 ( 0.0 89.802561 0.0) arc 1 0 ( 89.802561 0.0 0.0) arc 0 3 ( 0.0 -89.802561 0.0) arc 3 2 (-89.802561 0.0 0.0) arc 6 5 ( 0.0 89.802561 1.0) arc 5 4 ( 89.802561 0.0 1.0) arc 4 7 ( 0.0 -89.802561 1.0) arc 7 6 (-89.802561 0.0 1.0) );``` I also tried making a cylinder using pentagonal sides: Code: ```vertices ( ( 0.0 63.5 0.0) //0 (-60.392089 19.622579 0.0) (-51.372579 -37.324364 0.0) ( 51.372579 -37.324364 0.0) ( 60.392089 19.622579 0.0) ( 0.0 63.5 10.0) //5 (-60.392089 19.622579 10.0) (-51.372579 -37.324364 10.0) ( 51.372579 -37.324364 10.0) ( 60.392089 19.622579 10.0) ( 0.0 0.0 0.0) //10 ( 0.0 0.0 10.0) //11 ); blocks ( hex (10 0 1 10 11 5 6 11) (10 10 1) simpleGrading (1 1 1) hex (10 1 2 10 11 6 7 11) (10 10 1) simpleGrading (1 1 1) hex (10 2 3 10 11 7 8 11) (10 10 1) simpleGrading (1 1 1) hex (10 3 4 10 11 8 9 11) (10 10 1) simpleGrading (1 1 1) hex (10 4 0 10 11 9 5 11) (10 10 1) simpleGrading (1 1 1) ); edges ( arc 0 1 (-37.324364 51.372579 0.0) arc 5 6 (-37.324364 51.372579 10.0) arc 1 2 (-60.392089 -19.622579 0.0) arc 6 7 (-60.392089 -19.622579 10.0) arc 2 3 ( 0.0 -63.5 0.0) arc 7 8 ( 0.0 -63.5 10.0) arc 3 4 ( 60.392089 -19.622579 0.0) arc 8 9 ( 60.392089 -19.622579 10.0) arc 4 0 ( 37.324364 51.372579 0.0) arc 9 5 ( 37.324364 51.372579 10.0) );``` The latter obviously fails check mesh because the centre cells collapse to a point. I doubt these help at all, since what I want to know is how I can apply temperatures at single nodes (point BCs) in a radially-spaced perimetre about a circle.

 May 31, 2013, 12:14 #4 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,193 Blog Entries: 1 Rep Power: 16 dear body im afraid any one understand you correctly however, i feel you have a computational domain it seems its in cylindrical form, then you want to apply some special BC to it , 1- if those points are placed at a patch you can apply it from variables in 0 folder 2- if its internal node, you should use setFields to initiate a non-uniform initial condition 3- you can also use topoSet dict utilities to create an cellSet or faceSet __________________ Telegram channel (https://telegram.me/openfoam4Iranian) My Weblog (http://openfoam.blogfa.com/) Training Course on OpenFOAM at (http://www.isme.ir/)

 May 31, 2013, 12:37 #5 Member   Join Date: May 2013 Location: Canada Posts: 32 Rep Power: 5 nimasam, I appreciate you trying to help me out. Here's an image of what I'm trying to set up. Maybe it helps clear things up a bit? Concerning your first suggestion in your previous message, is it possible to assign a point location as a patch? My understanding was that you can only use points defined in the vertices, and when I try to set a patch as below it fails when I run blockMesh. Code: ```patches ( patch temp1 ( (0 0 0 0) ) );``` Ideally, this is what I want to do (set a patch at a point to set a constant temperature in my 0/T file). Last edited by cdm; May 31, 2013 at 12:47. Reason: Changed image link from imgur to Dropbox public.

 May 31, 2013, 12:41 #6 Senior Member   Nima Samkhaniani Join Date: Sep 2009 Location: Tehran, Iran Posts: 1,193 Blog Entries: 1 Rep Power: 16 unfortunately, i dont have access to pic link you can do this with codeStream ( i guess) or more easily with groovyBC in groovy BC, you can create a non-uniform variable in patch, so you can give an special point or region special BC you want __________________ Telegram channel (https://telegram.me/openfoam4Iranian) My Weblog (http://openfoam.blogfa.com/) Training Course on OpenFOAM at (http://www.isme.ir/)

 May 31, 2013, 12:48 #7 Member   Join Date: May 2013 Location: Canada Posts: 32 Rep Power: 5 Thanks, nimasam. I'll have a look at GroovyBC and update this post if I find a solution. Cheers.

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