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

Poor convergence with high streamwise loss multipler

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 21, 2011, 17:38
Default Poor convergence with high streamwise loss multipler
  #1
New Member
 
Join Date: Dec 2010
Posts: 26
Rep Power: 15
mullenc525 is on a distinguished road
Hi,
I am doing flow distribution analysis where I am using a porous media to simulate many small channels within a heat exchanger. I want to force the flow to be parallel within the porous media, which necessitates a high streamwise coefficient multiplier. The difficulty I am having is when I make the multiplier much bigger than 10, the solution convergence becomes highly oscillatory and I can't get good convergence.
Any ideas?
mullenc525 is offline   Reply With Quote

Old   September 21, 2011, 20:20
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,665
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
I suspect the tips here will be relevant:

http://www.cfd-online.com/Wiki/Ansys...gence_criteria
ghorrocks is offline   Reply With Quote

Old   September 23, 2011, 17:54
Default
  #3
New Member
 
David VanBronkhorst
Join Date: Sep 2011
Posts: 6
Rep Power: 14
dvanb is on a distinguished road
Apologies if I am not remembering this correctly, it's been a couple years since I did this kind of simulation, but:

you are saying you need a large stream-wise loss coefficient. I would think that in fact the directions _normal_ to the stream should have the very high loss coefficients to suppress crossflow. Your stream-wise coefficient should be whatever you need to simulate the expected pressure drop through the HEX for a given flow rate.
dvanb 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
how to understand high resolution scheme and high order scheme iilw1314 Main CFD Forum 7 April 12, 2022 13:29
Temperature loss in compressible solvers in high speed flows vkrastev OpenFOAM Running, Solving & CFD 1 June 16, 2018 08:10
loss calculation in simulation of turbomachines playmaster Main CFD Forum 0 August 21, 2010 06:59
Directional loss model Cenci CFX 6 December 20, 2005 15:33
Multicomponent fluid Andrea CFX 2 October 11, 2004 06:12


All times are GMT -4. The time now is 15:59.