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

time step size.

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

Reply
 
LinkBack Thread Tools Display Modes
Old   April 19, 2005, 23:40
Default time step size.
  #1
Sham
Guest
 
Posts: n/a
In the unsteady convergence, can some one pls tell me how to correctly calculate the time step size?

I'd also would like to know how to monitor for convergence for unsteady problem.

thanks.

Sham.
  Reply With Quote

Old   April 20, 2005, 00:14
Default Re: time step size.
  #2
Harish
Guest
 
Posts: n/a
Stability is the issue to be kept in mind. What kind of numerical scheme are you using.

-h
  Reply With Quote

Old   April 20, 2005, 03:15
Default Re: time step size.
  #3
Luca
Guest
 
Posts: n/a
Depends also on what frequency of your model you want to describe...Luca
  Reply With Quote

Old   April 20, 2005, 06:42
Default Re: time step size.
  #4
Sham
Guest
 
Posts: n/a
Thanks guys,

I am modelling a 2D pipeline on the seabed with a gap. This is to see the vortex shedding structure. I use an ske turbulence model.

Luca, I hope you can explain what do you mean what frequency of the model that I want to describe. I hope you guys can help me with this.

I'd really appreciate all the help.

Sham.
  Reply With Quote

Old   April 22, 2005, 18:02
Default Re: time step size.
  #5
Saad
Guest
 
Posts: n/a
You can use the explicit scheme in which the time step is automatically calculated by the FLUENT to satisfy the stability conditions.

Sincerely,

Saad
  Reply With Quote

Old   April 26, 2005, 06:59
Default Re: time step size.
  #6
anisa
Guest
 
Posts: n/a
The total time T=L/u, where L - length of your pipeline, u - inlet velocity. The pipeline length, for example 100m. In that case it is better to divited the length by 10000 parts, thus time step=T/10000, where 0 < time step < T.

I wish you every success!!!
  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
critical error during installation of openfoam Fabio88 OpenFOAM Installation 21 June 2, 2010 03:01
Modeling in micron scale using icoFoam m9819348 OpenFOAM Running, Solving & CFD 7 October 27, 2007 00:36
Transient simulation not converging skabilan OpenFOAM Running, Solving & CFD 12 September 17, 2007 17:48
natural convection - time step size co2 FLUENT 7 June 3, 2004 21:56
how to increase time step size? co2 FLUENT 6 May 17, 2004 07:25


All times are GMT -4. The time now is 19:22.