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

find the cell(s) related to maximum continuity residual

Register Blogs Community New Posts Updated Threads Search

Like Tree1Likes
  • 1 Post By Fabio88

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 11, 2014, 14:49
Default find the cell(s) related to maximum continuity residual
  #1
Senior Member
 
Joe
Join Date: Feb 2012
Location: Canada
Posts: 112
Rep Power: 14
enayath is on a distinguished road
Hello,

I am wondering if there is a way to find out the position of the cell(s) that has high continuity residual. In my calculation I got the order of 10e5 for the continuity residual. As far I know, the number we see in the continuity residual is the maximum value in all domain. So in my calculation maybe there are a few number of elements that cause such a high value for continuity. In this case I can refine my mesh in that particular area and got correct answer.

Any idea ?

Thank you in advance!
Hooman
enayath is offline   Reply With Quote

Old   July 24, 2016, 11:38
Default
  #2
Member
 
Fabio Malizia
Join Date: May 2010
Location: Leuven (Belgium)
Posts: 51
Rep Power: 16
Fabio88 is on a distinguished road
Hi Enayath,

I have a similar problem.
Did you find a way to find out the cells that cause bad residuals?

I would really appreciate if you can help me.

Fabio
Fabio88 is offline   Reply With Quote

Old   July 24, 2016, 11:47
Default
  #3
Senior Member
 
Joe
Join Date: Feb 2012
Location: Canada
Posts: 112
Rep Power: 14
enayath is on a distinguished road
Hello Fabio,

I really do not remember how I could fix it. However, I can say you need to refine the mesh close to the boundary layers or change the settings...like time step or use Simple or Piso...If you use Design modeler and Meshing, you can find the quality or skewness or the relevant information after making the mesh in Meshing. You can check the number and the position of the bad elements in Meshing...go to statics and choose element quality or skewness or orthogonality to find the bad elements...You can also send me your case if you would like...I can take a look.

Good Luck,
Hooman
enayath is offline   Reply With Quote

Old   July 25, 2016, 06:06
Default
  #4
Member
 
Fabio Malizia
Join Date: May 2010
Location: Leuven (Belgium)
Posts: 51
Rep Power: 16
Fabio88 is on a distinguished road
Hi Enayath,

thanks a lot for the help.

I found a way to visualize which cells have bad residuals:

If you type: solve/set/expert you get the following questions:
Save cell residuals for post-processing? [no]
Keep temporary solver memory from being freed? [no]
Allow selection of all applicable discretization schemes? [no]

For the first write YES for the others keep no.
Run one iteration.
now you can visualize the contours of the residuals. I just made some isoclips of the higher residuals.

I think these are real residuals and not scaled ones, since I get also some negative one.

Do you think is a correct method?

Fabio
SphericalCube likes this.
Fabio88 is offline   Reply With Quote

Old   July 25, 2016, 10:48
Default
  #5
Senior Member
 
Joe
Join Date: Feb 2012
Location: Canada
Posts: 112
Rep Power: 14
enayath is on a distinguished road
Fabio,

Unluckily, I have no idea how does it work!

Hooman
enayath 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
Floating point exception error Alan OpenFOAM Running, Solving & CFD 11 July 1, 2021 22:51
High Courant Number @ icoFoam Artex85 OpenFOAM Running, Solving & CFD 11 February 16, 2017 14:40
Extrusion with OpenFoam problem No. Iterations 0 Lord Kelvin OpenFOAM Running, Solving & CFD 8 March 28, 2016 12:08
Micro Scale Pore, icoFoam gooya_kabir OpenFOAM Running, Solving & CFD 2 November 2, 2013 14:58
Problems with simulating TurbFOAM barath.ezhilan OpenFOAM 13 July 16, 2009 06:55


All times are GMT -4. The time now is 22:16.