CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > STAR-CCM+

rasidual in each cell, location of the cells with maximum residuals

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

Like Tree2Likes
  • 2 Post By azt

Reply
 
LinkBack Thread Tools Display Modes
Old   November 28, 2013, 09:48
Default rasidual in each cell, location of the cells with maximum residuals
  #1
New Member
 
Join Date: Oct 2013
Posts: 21
Rep Power: 3
flux is on a distinguished road
Hi,

is there any posibility to show me the positions of the cells, which have the highest residuals?

I couldn't find something in the manual...


THX!
flux is offline   Reply With Quote

Old   November 28, 2013, 10:23
Default
  #2
Member
 
Join Date: Jul 2013
Posts: 37
Rep Power: 3
Alex C. is on a distinguished road
One thing you can do, is create a user-defined field function which correspond to your model.

If you are using an incompressible, then
\nabla \vec{V} = 0

Therefore, if you create a field function which is div(V), it should show values near 0 in each cell.

The value I suggest you display will not be the same as residuals, but at least it can show you what part of the domain is less precise.

You can also create field-function for momentum equations, and eventually energy and turbulence, if you want to.
Alex C. is offline   Reply With Quote

Old   November 28, 2013, 11:48
Default residuals
  #3
azt
Member
 
allan thomson
Join Date: Mar 2009
Location: scotland
Posts: 39
Rep Power: 8
azt is on a distinguished road
Hi

There is an easier way.

If you're using the segregated solver then:

solver -> segregated flow-> check the temporary storage retained box in the expert properties window

and run for 1 iteration.

The momentum residuals will be written out to field functions.

azt
crevoise and Alex C. like this.
azt is offline   Reply With Quote

Old   November 29, 2013, 05:53
Default
  #4
New Member
 
Join Date: Oct 2013
Posts: 21
Rep Power: 3
flux is on a distinguished road
ok thx...

now i've got field functions with the residuals... but how can i see the distribution over the cells... a scalar scene didn't show anything...
flux is offline   Reply With Quote

Old   November 29, 2013, 08:57
Default stuff
  #5
azt
Member
 
allan thomson
Join Date: Mar 2009
Location: scotland
Posts: 39
Rep Power: 8
azt is on a distinguished road
Hi
you should be able to plot these as a scalar field.

you can createa report that gives you the max and min values. You can then create a threshold with say the top 10% and bottom 10% value and plot this.

That's how you do it.

azt
azt is offline   Reply With Quote

Old   November 29, 2013, 10:18
Default
  #6
New Member
 
Join Date: Oct 2013
Posts: 21
Rep Power: 3
flux is on a distinguished road
hm... i don't get any scalar-field plots.

i created a new scalar scene. Under displayers/Scalar 1, I added (under Parts) my fluid region. Under scalar field, i choose a Residual-field-function and nothing is happening.

It seems that this values are empty... because it does not show any Min/Max Values.

edit:

i forgot to say, that i am using a cluster... so on my desktop-pc, the values are available... is there any way to save the field functions in the .sim file?

there is another question: some residuals are negative... is there a way to get the values of residuals, which are displayed in the residual-plot?
flux is offline   Reply With Quote

Old   November 30, 2013, 05:17
Default stuf
  #7
azt
Member
 
allan thomson
Join Date: Mar 2009
Location: scotland
Posts: 39
Rep Power: 8
azt is on a distinguished road
hi

you can't save temporary storage stuff to the sim file, which is a real pain. However you can write out the scaler field to a table file, and read it in later on.

azt
azt is offline   Reply With Quote

Old   December 2, 2013, 06:33
Default
  #8
New Member
 
Join Date: Oct 2013
Posts: 21
Rep Power: 3
flux is on a distinguished road
hi, thx! can you give me a short instruction, how to write out a scalar field to a table file?
flux is offline   Reply With Quote

Old   December 3, 2013, 07:26
Default
  #9
azt
Member
 
allan thomson
Join Date: Mar 2009
Location: scotland
Posts: 39
Rep Power: 8
azt is on a distinguished road
hi
tools -> tables -> right click -> new table -> xyz internal table

chose parts and scalars you want to export

then right click -> extract then right click export

Read this file in later and create a field function using the function InterpolatePositionTable

see help for syntax

azt
azt is offline   Reply With Quote

Old   December 10, 2013, 09:48
Default
  #10
New Member
 
Join Date: Oct 2013
Posts: 21
Rep Power: 3
flux is on a distinguished road
sorry for my late answer! i will try it, thx!
flux 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
Solution Diverging with Trimmer Mesh rietuk STAR-CCM+ 8 February 27, 2013 05:50
Snappy creates strange cells far away from boundary vainilreb OpenFOAM Native Meshers: snappyHexMesh and Others 1 February 14, 2013 05:44
cgnsToFoam problems with "QUAD_4" cells lentschi OpenFOAM Meshing & Mesh Conversion 1 March 9, 2011 05:49
Errors running allwmake in OpenFOAM141dev with WM_COMPILE_OPTION%3ddebug unoder OpenFOAM Installation 11 January 30, 2008 21:30
Ghost cell location for inclined cavity flow zonexo Main CFD Forum 13 September 9, 2005 02:00


All times are GMT -4. The time now is 17:35.