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

Will refining the grid help in better convergence?

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   February 4, 2018, 10:36
Exclamation Will refining the grid help in better convergence?
  #1
New Member
 
Noel
Join Date: Apr 2017
Posts: 7
Rep Power: 8
knax is on a distinguished road
My 3D mesh with K-omega simulation of a fan has a pretty good quality, with just a few cells out of 0.8 million with an orthogonal skewness >0.7. However, the residuals are stagnating at just about 10e-3 for velocities and 10e-2 for continuity.

Any suggestions?
knax is offline   Reply With Quote

Old   February 5, 2018, 08:59
Default
  #2
Member
 
Kirill-MIPT's Avatar
 
Kirill Borodin
Join Date: Mar 2016
Posts: 60
Rep Power: 9
Kirill-MIPT is on a distinguished road
Hello! Please show the mesh and tell which boundary conditions do you use. Which y+ value did you try to obtain?
Kirill-MIPT is offline   Reply With Quote

Old   February 5, 2018, 12:40
Default
  #3
Senior Member
 
Gert-Jan
Join Date: Oct 2012
Location: Europe
Posts: 1,814
Rep Power: 27
Gert-Jan will become famous soon enough
Which k-omega model?
And settings?
Gert-Jan is offline   Reply With Quote

Old   February 5, 2018, 15:51
Default
  #4
Member
 
Kirill-MIPT's Avatar
 
Kirill Borodin
Join Date: Mar 2016
Posts: 60
Rep Power: 9
Kirill-MIPT is on a distinguished road
I mean pressure, temperature and velocity/Mach number in the inlet
Kirill-MIPT is offline   Reply With Quote

Old   April 11, 2018, 01:09
Smile Sorry for the later reply. Didn't get notified. How does Fuent calculate residuals?
  #5
New Member
 
Noel
Join Date: Apr 2017
Posts: 7
Rep Power: 8
knax is on a distinguished road
Hi Kirill and Gert,

Sorry for the later reply. I didn't use y+ for first layer thickness. I used AR of 10 for k-omega (standard).

I'm simulation an axial fan with MRF. 1st inflation layer AR=10 on all walls.

Only pressure outlets. With an RPM of 2500. I worked on max orthogonal skewness and brought it down to 0.7. I've get my residuals to 10e-4 and the parameters of total-pressure and heat-flux are not changing. Hence, I've taken them to have converged. But I just wanted insight into how Fluent actually calculates residuals. Thanks!

Kind regards,

Noel
knax is offline   Reply With Quote

Reply

Tags
convergence, fan, refinement, residuals

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Grid Convergence Study Hybrid Pointwise & Gridgen 5 April 18, 2016 10:40
Force can not converge colopolo CFX 13 October 4, 2011 23:03
Convergence of CFX field in FSI analysis nasdak CFX 2 June 29, 2009 02:17
Re: Convergence problem for refined grid CFD_Novice Main CFD Forum 13 February 17, 2008 23:56
Convergence on non-uniform grid dragon Main CFD Forum 2 January 31, 2005 03:23


All times are GMT -4. The time now is 11:11.