CFD Online Logo CFD Online URL
Home > Forums > General Forums > Main CFD Forum

Double precision does not converge, Single precision does

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

LinkBack Thread Tools Search this Thread Display Modes
Old   May 7, 2015, 09:16
Default Double precision does not converge, Single precision does
New Member
Jan Michielsen
Join Date: Mar 2015
Posts: 4
Rep Power: 8
jmmichie is on a distinguished road
Hi all,

I'm doing a crosswind analysis of a train and have found the following problem.
When solving with the double precision solver, my monitored coefficients such as lift, drag, ... do converge after some iterations, however my scaled residuals get stuck at 1 e-02 (continuity only).
When solving with the single precision solver, my residuals have no problem dropping below 1e-05, but the converged values of lift etc. differ somewhat from the ones found with double precision.

I know double precision normally is the more accurate, but can I conclude this when my scaled residuals of continuity get stuck at 1 e-02??

Thanks in advance,

PS: I'm using the k-omega turbulence model and wall functions (y+30). I have tried using y+=1, where the scaled residuals where somewhat less but they got stuck at 5 e-03.
jmmichie is offline   Reply With Quote


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
CFD by anderson, chp 10.... supersonic flow over flat plate varunjain89 Main CFD Forum 18 May 11, 2018 08:31
Continuing User Defined Real Gas Model issues aeroman FLUENT 6 April 8, 2016 04:34
Missing math.h header Travis FLUENT 4 January 15, 2009 12:48
what's wrong about my code for 2d burgers equation morxio Main CFD Forum 3 April 27, 2007 11:38
REAL GAS UDF brian FLUENT 6 September 11, 2006 09:23

All times are GMT -4. The time now is 17:23.