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

Free Surface Problem - Convergance

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

Reply
 
LinkBack Thread Tools Display Modes
Old   July 2, 2008, 23:16
Default Free Surface Problem - Convergance
  #1
Toby
Guest
 
Posts: n/a
Hi,

I am running some 2D cases of planing flate plates with an unsteady free surface (air-water) model, using an explicit scheme.

This is fine, except that I seem to have to use very small time steps (of the order of 1x10^(-6)) for the solution to converge to residuals of 1x10^(-4) at each time step. The flow velocity is quite high ~ 20 m/s so this is probably to be expected.

Since I am not really interested in the transient behaviour of the solution, I beleive it is okay if the residuals do not converge at each time step, as long as they are within reasonable limits. Of the simulations I have run so far, I certainly seem to get unreasonable results when the residuals do not converge sufficiently.

What I would like to know is whether there is any other ways of speeding the convergance? I have used implicit body force formulation which seemed to increase the convergance rate somewhat, but am not sure if I could make any other simplifications which might make the solution a bit faster?

Thanks

Toby
  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
free surface problem vuthuan FLUENT 0 February 1, 2009 22:00
CFX Free Surface problem sam CFX 6 March 21, 2007 19:49
Free surface problem Luk CFX 2 July 27, 2006 01:07
free surface problem PLEASE HELP ME varshavian FLUENT 1 February 17, 2003 07:07
Free surface problem chang CFX 0 November 13, 2002 12:49


All times are GMT -4. The time now is 02:33.