CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Programming & Development

Interpolation on a 3D grid

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   June 1, 2012, 08:39
Default Interpolation on a 3D grid
  #1
Senior Member
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Leoben (Austria)
Posts: 1,077
Blog Entries: 4
Rep Power: 19
Tobi will become famous soon enough
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Hi all,

i am not sure where to put that threat into and hope thats okay.
Its not an especially question to openfoam but maybe some of you know the math descriptions about that. So my question is:

Do anyone know a equation, math construct or references for interpolation on a 3D grid.
Well I am just interested in the equations or the general description of such a problem.

An example:

You `ve a scalar value phi (like temperature, cp, mu, or sth. like that) depended on two variables like Z and Z".
You solve two transport equations with openFoam to get Z and Z" and wanna get phi out of a table. The table is a three-dimensional graphic like described befor. The problem is, that phi is generated with some grid points e.g. 100 points in Z direction an 40 points in Z" direction.

So if you get values for f and f" not being direct on a given point on the grid you have to interpolate the value phi.
Well I have a solution and know how it works but do not know if there are special literature or references.
The interpolation used in my case is shown here (my post too):

http://www.matheboard.de/thread.php?...ightuser=52671


well hope someone can give me an advice.

tobi
Tobi is offline   Reply With Quote

Old   June 1, 2012, 08:53
Default
  #2
Senior Member
 
Arne Stahlmann
Join Date: Nov 2009
Location: Hanover, Germany
Posts: 209
Rep Power: 8
Arnoldinho is on a distinguished road
Hi,

you could e.g. have a look at the 'Shepard Method', which is distance weighted interpolation in 3D: http://www.ems-i.com/gmshelp/Interpo...rds_Method.htm.
I'm not sure if this it directly want you need, but I successfully use it e.g. for surface terrain interpolation.

Greetings,

Arne
Arnoldinho is offline   Reply With Quote

Old   June 1, 2012, 11:44
Default
  #3
Senior Member
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Leoben (Austria)
Posts: 1,077
Blog Entries: 4
Rep Power: 19
Tobi will become famous soon enough
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
hi,

thx for your replay. Its sounds interessting but I am not sure if its the correct one like mine.

I am not very familiar with those interpolations.
Can you have a look at the PDF? Do anyone know sth. like that?

Thx in advance and I ll check your link and the equations again.
Tobi


here its like area weighted
Attached Files
File Type: pdf schemes.pdf (52.0 KB, 15 views)
Tobi is offline   Reply With Quote

Old   June 2, 2012, 10:50
Default
  #4
Senior Member
 
Arne Stahlmann
Join Date: Nov 2009
Location: Hanover, Germany
Posts: 209
Rep Power: 8
Arnoldinho is on a distinguished road
No, I unfortunately do not know this interpolation type.
But what exactly are you looking for now? The name and theory of your interpolation given in the pdf, or an alternative for this?

Greetings,
Arne
Arnoldinho is offline   Reply With Quote

Old   June 2, 2012, 11:01
Default
  #5
Senior Member
 
Tobi's Avatar
 
Tobias Holzmann
Join Date: Oct 2010
Location: Leoben (Austria)
Posts: 1,077
Blog Entries: 4
Rep Power: 19
Tobi will become famous soon enough
Send a message via ICQ to Tobi Send a message via Skype™ to Tobi
Quote:
Originally Posted by Arnoldinho View Post
No, I unfortunately do not know this interpolation type.
But what exactly are you looking for now? The name and theory of your interpolation given in the pdf, or an alternative for this?

Greetings,
Arne

Hi Arne, i am looking for the name and theory of that interpolation in my case ... but thx for your advice
Tobi is offline   Reply With Quote

Reply

Thread Tools
Display Modes

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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
momentum interpolation for collocated grid Hadian Main CFD Forum 4 December 25, 2009 08:25
Interpolation on the unstructured grid ztdep Main CFD Forum 2 July 8, 2009 09:35
GRID TO GRID INTERPOLATION in FLUENT calogero FLUENT 3 June 4, 2003 08:32
Combustion Convergence problems Art Stretton Phoenics 5 April 2, 2002 05:59
Troubles modelling flow through a grid Hans Klaufus CFX 1 June 28, 2000 16:43


All times are GMT -4. The time now is 04:12.