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

pressure outlet condition

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

Reply
 
LinkBack Thread Tools Display Modes
Old   October 7, 2004, 07:30
Default pressure outlet condition
  #1
Aly
Guest
 
Posts: n/a
Hello Fluent Users

I am user user of fluent and i am modelling two phase, air-water flow in vertcial pipe. i am using mixture model and boundary conditions are two velocity inlets at the bottom, one for water other for air and the outlet boundary condition is pressure outlet. I am defining opertaing pressure at atmospheric at refernce location on the top of the pipe.

Although i did manage to get some results but i think they are not correct as there is mass imbalance, residuals of continuity being too high, k-e residuals going too high (spikes) and most importantly the velocity of air although defined at 4.4. m/s at inlet show a value of 4.4 m/s at start of inlet and and than shows patch values of 10 m/s in core and when it enters the main pipe it shows 2.55 to 3.55 m/s. I can't understand whether its the boundary conditions that making this probelm or using refernce pressure location at the top of the pipe.

any suggestions..............???

Aly
  Reply With Quote

Old   October 9, 2004, 00:07
Default Re: pressure outlet condition
  #2
Aravind
Guest
 
Posts: n/a
Hi,

There are two things which you can do here. One, the atmospheric pressure defined as default in Fluent is zero gauge pressure, meaning all B.C's have to defined with the gauge pressure. Two, in the menu's under the Report menu, look for reference values, change that according to your conditions and geometry, sometimes this might affect your results. Three, try using a different solver scheme, you can use the Quick scheme, instead of first order upwind or second order upwind. hope this helps, Aravind
  Reply With Quote

Reply

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
simple model, difficult outlet Eric CFX 7 May 23, 2014 08:13
Static pressure boundary condition at outlet jennz CFX 4 February 11, 2014 04:29
Setting outlet Pressure boundary condition using CAFFA code Mukund Pondkule Main CFD Forum 0 March 16, 2011 04:23
Using pressure outlet BC Shreyansh FLUENT 0 November 5, 2010 15:57
Natural Convection (Operating Pressure condition) Andrew Tress FLUENT 1 July 3, 2006 18:27


All times are GMT -4. The time now is 04:33.