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

How to suppress convection & viscous effects using CFX

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

Reply
 
LinkBack Thread Tools Display Modes
Old   January 17, 2011, 21:40
Default How to suppress convection & viscous effects using CFX
  #1
New Member
 
Hareesh R Iyer
Join Date: Dec 2010
Location: Thiruvananthapuram
Posts: 20
Rep Power: 6
Haga is on a distinguished road
In a free surface transient flow problem of a fluid in a partially filled container, how can one reduce or suppress the effect of convection & viscosity theoretically & using CFX?? Is it possible to achieve this simultaneously or would there be a need of compromising anything to achieve this condition?
Haga is offline   Reply With Quote

Old   January 18, 2011, 19:18
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,824
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
You cannot model inviscid flows in CFX, but you can specify a viscosity so low that it is effectively zero. This is easy, but may cause convergence problems especially for free surface problems.

CFX is a Navier Stokes solver so solution of convection is inherent. I cannot see how a free surface simulation could be driven by diffusion only. Can you explain why you want to stop convection?
ghorrocks is offline   Reply With Quote

Old   January 31, 2011, 21:09
Default @ Glenn
  #3
New Member
 
Hareesh R Iyer
Join Date: Dec 2010
Location: Thiruvananthapuram
Posts: 20
Rep Power: 6
Haga is on a distinguished road
1st of all...Thanks for replying...

Viscous effects as u said can be controlled so. But what is the use of convective term in a free surface problem of a liquid inside a container? If it was flowing, then convective effects can be considered. Since there's no liquid motion other than oscillation why it is that the convective effect be kept considered while doing the model?
Haga is offline   Reply With Quote

Old   February 1, 2011, 18:31
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,824
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
If the fluid is moving then convective effects are contributing. If the fluid is not moving then forget CFD and it work out by far simpler methods.

So what are you trying to do?
ghorrocks is offline   Reply With Quote

Reply

Tags
convection, free surface, suppress, viscous

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
Pros and Cons for CFX, CFdesign, COMSOL Val Main CFD Forum 3 June 10, 2011 02:20
ATTENTION! Reliability problems in CFX 5.7 Joseph CFX 14 April 20, 2010 15:45
viscous effects in hypersonic flow (at high Re no) VVJ Main CFD Forum 1 November 20, 2007 09:35
CFX 4.4 installation problem Pandu Sattvika CFX 1 December 1, 2001 05:07
How to obtain correct viscous pressure drag using CFX? Ketut Utama Main CFD Forum 1 January 25, 1999 06:05


All times are GMT -4. The time now is 12:25.