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

Need help : natural convection in inclined convergent channel

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   October 21, 2012, 12:08
Default Need help : natural convection in inclined convergent channel
  #1
New Member
 
Join Date: Oct 2012
Posts: 1
Rep Power: 0
Glare is on a distinguished road
hello all, first of all, sorry for my bad english
im still newbie here and hope to get some help

i have some problem on inclined convergent channel system.

The system has 2 inclined wall with same temperatur (i set 332K for both wall). The bottom & top temperatur is set to 300K. The bottom side is inlet and the top side is outlet. What boundary condition should i choose for top & bottom? is that true if i set the top & bottom side of system is set to pressure outlet & pressure inlet?

In material panel, i set density properties to boussinesq, should i change its value (default value = 0)?

When i have convergence problem, i try to change the under relaxation factor, i decrease it gradually until the residual almost constant. Is there any limit value in decreasing uder relaxation factor?

Any help would be very useful to me, thanks
Glare is offline   Reply With Quote

Old   October 21, 2012, 12:31
Default
  #2
Senior Member
 
SSL
Join Date: Oct 2012
Posts: 226
Rep Power: 14
msaeedsadeghi is on a distinguished road
1- Don't change fluent default values without information
2- You should define that density value. Set the density. Zero is incorrect.
3- If you have a natural convection in a closed box, all boundary conditions should be as wall.
4- Natural convection is highly sensitive to mesh size. change it to get a good result.
msaeedsadeghi is offline   Reply With Quote

Reply


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
natural convection problem with radiation jorien CFX 0 October 14, 2011 09:26
modeling natural convection in tilted channel Luis FLUENT 0 April 27, 2008 15:56
Coupled vs Seg - Natural vs. Forced Convection Alex Siemens 5 December 12, 2007 04:58
Approximate Mixing due to Natural Convection Greg Perkins Main CFD Forum 0 February 12, 2003 18:43
natural convection in a sealed enclosure James Main CFD Forum 4 April 2, 2001 15:48


All times are GMT -4. The time now is 23:52.