CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM

Point BCs for Heat Transfer Problem

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 30, 2013, 21:19
Default Point BCs for Heat Transfer Problem
  #1
cdm
Member
 
Join Date: May 2013
Location: Canada
Posts: 32
Rep Power: 13
cdm is on a distinguished road
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.
cdm is offline   Reply With Quote

Old   May 31, 2013, 04:17
Default
  #2
Senior Member
 
Nima Samkhaniani
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,267
Blog Entries: 1
Rep Power: 25
nimasam is on a distinguished road
dear body

please read this post, then post enough information here, then forum users will help you
__________________
My Personal Website (http://nimasamkhaniani.ir/)
Telegram channel (https://t.me/cfd_foam)
nimasam is offline   Reply With Quote

Old   May 31, 2013, 13:05
Default
  #3
cdm
Member
 
Join Date: May 2013
Location: Canada
Posts: 32
Rep Power: 13
cdm is on a distinguished road
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.
cdm is offline   Reply With Quote

Old   May 31, 2013, 13:14
Default
  #4
Senior Member
 
Nima Samkhaniani
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,267
Blog Entries: 1
Rep Power: 25
nimasam is on a distinguished road
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
__________________
My Personal Website (http://nimasamkhaniani.ir/)
Telegram channel (https://t.me/cfd_foam)
nimasam is offline   Reply With Quote

Old   May 31, 2013, 13:37
Default
  #5
cdm
Member
 
Join Date: May 2013
Location: Canada
Posts: 32
Rep Power: 13
cdm is on a distinguished road
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 13:47. Reason: Changed image link from imgur to Dropbox public.
cdm is offline   Reply With Quote

Old   May 31, 2013, 13:41
Default
  #6
Senior Member
 
Nima Samkhaniani
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,267
Blog Entries: 1
Rep Power: 25
nimasam is on a distinguished road
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
__________________
My Personal Website (http://nimasamkhaniani.ir/)
Telegram channel (https://t.me/cfd_foam)
nimasam is offline   Reply With Quote

Old   May 31, 2013, 13:48
Default
  #7
cdm
Member
 
Join Date: May 2013
Location: Canada
Posts: 32
Rep Power: 13
cdm is on a distinguished road
Thanks, nimasam. I'll have a look at GroovyBC and update this post if I find a solution. Cheers.
cdm is offline   Reply With Quote

Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
problem in toposet Ahmed Khattab OpenFOAM Pre-Processing 27 March 3, 2023 22:12
problem in turbulent flow over flat plate with stagnation point mb.pejvak Main CFD Forum 0 September 12, 2012 22:25
[blockMesh] error EOF in blockMesh Ahmed Khattab OpenFOAM Meshing & Mesh Conversion 7 May 17, 2012 01:37
Isolated walls in heat transfer problem Maria FLUENT 1 August 13, 2007 07:04
CFX4.3 -build analysis form Chie Min CFX 5 July 13, 2001 00:19


All times are GMT -4. The time now is 13:15.