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

unsteady solver/bouyancy flow

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

LinkBack Thread Tools Display Modes
Old   July 16, 2010, 13:52
Default unsteady solver/bouyancy flow
Join Date: Mar 2010
Location: Canada,Ontario
Posts: 31
Rep Power: 7
engahmed is on a distinguished road
Hi, I am modelling bouyancy flow from a hot horizontal cylinder enclosed by pressure boundary conditions domain in 2D. As per fluent advanced lectures, natural convection around abstacles must be modeled using the unsteady solver. That is what I am trying to do but I noticed that whatever number of maximum iterations per time step I define, i never get convergence at each time step, i even used 10000 iterations per time step!
My time step size is 0.6, calculated from:
Time step={square root[characterestic length/(beta*delta T*g)]}/4
So I am wondering what is wrong or what should I do? Even when i disregard this problem and wait for overall convergence i never get it, the net heat transfer never becomes zero it is either less than or more than zero.
Any help will be appreciated.
Thank you.
engahmed is offline   Reply With Quote


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
how to predict unsteady flow from case definition? Felix Main CFD Forum 6 August 28, 2007 16:40
Unsteady flow in FLUENT Vidya Raja FLUENT 2 November 2, 2005 17:29
Unsteady Boundary Layer Flow Wen Long Main CFD Forum 0 July 29, 2002 23:08
fluid flow fundas ram Main CFD Forum 5 June 17, 2000 21:31
computation about flow around a yawed cone Tylor Xie Main CFD Forum 0 June 9, 1999 07:33

All times are GMT -4. The time now is 17:56.