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

Implicit Timestep

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   July 14, 2011, 17:21
Default Implicit Timestep
  #1
New Member
 
Join Date: Jul 2011
Posts: 2
Rep Power: 0
kingbob is on a distinguished road
Hi, I had a quick question dealing with time steps in an implicit solution. I am dealing with transient system and finding that 1e-7 was taking to long to stabilize, so during the middle of the simulation i stopped and changed the time step to 1e-6. My question is will this introduce error, I do fully understand higher time step yields solution faster with less accuracy, my question deals more with am I creating a hole or effecting the results in a way that would invalidate them.

So I guess I am asking, does changing the time step create unacceptable noise in the solution after the change. I am actually only interested in the steady state solution, so I am not sure if it even matters.
kingbob is offline   Reply With Quote

Old   July 21, 2011, 01:59
Default
  #2
Senior Member
 
Join Date: Mar 2009
Location: Indiana, US
Posts: 186
Rep Power: 17
delaneyluke is on a distinguished road
It is a common practice, for unsteady flows, to start with a low TS and then gradually increase it as time progresses. It will not affect your flow as long as the higher TS leads to a converged flow. Check the value of Courant Number in your domain whenever you adjust the TS, a value <10 should be acceptable.
delaneyluke is offline   Reply With Quote

Reply

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
Restart 2-way FSI with different timestep? Lance CFX 10 April 17, 2013 01:37
Help. implicit discritization dearboy Main CFD Forum 0 November 25, 2010 22:46
need for an unsteady implicit solver suitable for large timestep dinonettis OpenFOAM 2 May 26, 2010 07:57
Can anyone explain the difference between these implicit concepts? bearcat Main CFD Forum 0 February 20, 2010 19:39
Use of Timestep in obtaining solution. hagupta CFX 7 February 28, 2006 14:14


All times are GMT -4. The time now is 21:25.