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

CFX Streamline Curvature Correction model

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 28, 2010, 03:32
Default CFX Streamline Curvature Correction model
  #1
New Member
 
Join Date: May 2010
Posts: 4
Rep Power: 0
flow.pratish is on a distinguished road
CFX 12.0 has got a streamline curvature correction model. Also, it provides few parameteric tuning into it, such as CSCALE. When to use this model ? and what shall be the range of values for CSALE ? Would be greatfull if someone tells about why its to be used ..
flow.pratish is offline   Reply With Quote

Old   May 28, 2010, 08:47
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
It is to correct turbulence generation in strongly swirling flows. Don't fiddle with the constants unless you REALLY know what you are doing, and certainly not before reading the literature about what the constants mean.
ghorrocks is offline   Reply With Quote

Old   May 28, 2010, 08:52
Default
  #3
New Member
 
Join Date: May 2010
Posts: 4
Rep Power: 0
flow.pratish is on a distinguished road
Thanks Glenn for the reply. Exactly the same flow i am trying to simulate which has strong swirls in it. However, the solution shows intense variation as I change the parameter CSCALE value over small ranges ....
flow.pratish is offline   Reply With Quote

Old   May 28, 2010, 08:59
Default
  #4
New Member
 
Join Date: May 2010
Posts: 4
Rep Power: 0
flow.pratish is on a distinguished road
even in smaller range of values for CSCALE, such as, 1, 1.5 and 2.0, the solution varies immensly. The CFX Solver theory guide do not talk about any guidance on it. They do not suggest any range for it. For how much intense swirl flow what value of cscale one shall belive on ? no idea. Secondly, if the sreamline curvature correction model does take care of the curvature effect due to swirl flow then why shall we need the cscale ?
flow.pratish is offline   Reply With Quote

Old   May 28, 2010, 09:07
Default
  #5
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
Quote:
The CFX Solver theory guide do not talk about any guidance on it.
As I said, there should be a literature reference for the model in the documentation. You won't get anywhere until you follow that up. Do not fiddle with the constants until you know what they mean.

Whether you need the curvature correction model or not is up to you. Run with it and without it and see if it makes a difference to your models. Also keep in mind that other turbulence models may be more appropriate such as RSM or LES. 2-equation turbulence models are well known to have problems with strongly swirling flows.
ghorrocks is offline   Reply With Quote

Old   May 28, 2010, 09:59
Default
  #6
New Member
 
Join Date: May 2010
Posts: 4
Rep Power: 0
flow.pratish is on a distinguished road
yes Glenn, i googled through the CFX document for streamline curvature correction model, which pointed to Literature article by Spalart & Shur.
I checked with the article as well, surprisingly, the original model as in the article does not talk about any scaling factor as such.
flow.pratish is offline   Reply With Quote

Old   May 29, 2010, 08:10
Default
  #7
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
You would have to talk to CFX support for more detailed information about this model then.
ghorrocks is offline   Reply With Quote

Old   August 29, 2012, 16:44
Default
  #8
Member
 
Hesam Moghaddam
Join Date: Mar 2012
Posts: 49
Rep Power: 14
hesamking is on a distinguished road
I am simulating blood flow in an artery and my streamlines doesn't start from inlet and their shape is swirling instead of straight through the artery (pipe). do u have any idea what the problem can be?
I have attached the pic
thanks,
Attached Images
File Type: bmp CFX_010.bmp (56.8 KB, 30 views)
hesamking is offline   Reply With Quote

Old   August 29, 2012, 19:32
Default
  #9
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
Your image is unreadable.

But the problem is going to be in your setup, or it is not fully converged.

Please do not hijack threads. For a new question start a new thread.
ghorrocks 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
CFX Liquid Evaporation Model Jinx CFX 3 January 28, 2010 17:31
Import Fan 3D Model - Workbench or CFX? Stewart Long CFX 2 October 28, 2008 05:05
How to use the competing reaction model in CFX 11 NewCoalman CFX 0 May 5, 2008 04:15
where to set CFX Transition Model? steven CFX 6 January 17, 2007 12:19
Use of 1 equation turbulence model in CFX 4.3 Niels Deen CFX 0 July 19, 2000 09:50


All times are GMT -4. The time now is 18:47.