CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT

VOF model

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

LinkBack Thread Tools Search this Thread Display Modes
Old   April 15, 2005, 06:57
Default VOF model
Posts: n/a

i am trying to simulate the water-air interface in vertcial pipe. I am using unsteady state VOF model. I started my case as steady state single phase (water)simulation to have velocity field developed and later turn on the VOF model. The problem i am experinecing is: I define water velocity at the inlet (bottom of the pipe)at the start of the steady state run but when I switch to unsteady solution and turn ON the VOF model (geo-recons)..... to enter the boundary conditon for air velocity ( at the separate inlet) it does not display the box for the input of the air velocity but just the volume fraction box.

Am i missing something? help needed.

  Reply With Quote

Old   April 15, 2005, 08:22
Default Re: VOF model
Posts: n/a
hi there

I just looked at fluent manual VOF model option since single momentum equation is shared between the phases meaning only one velocity.

If i have single phase steady state soltuion (i.e. developed velocity field for water) and than i introduce the VOF model .........I only need to specify volume fraction for other phase? now the question is that does it means that air velocity is calculated from the multiplication of volume fraction and water velocity during the calculations in cell?

How am i suppose to take into account the entrance air velocity from separate inlet which is different than water velocity?
  Reply With Quote

Old   April 15, 2005, 16:17
Default Re: VOF model
Srinivas Parimi
Posts: n/a
Hello Aly,

To introduce separate velocities for two phases as inlet, I think you have to use the mixture model. In VOF you can only specify the primary phase velocity and the VOF of the secondary phase.

all the best

srinivas parimi
  Reply With Quote

Old   April 22, 2005, 13:43
Default Re: VOF model
majid mirzabeagi
Posts: n/a
I am student and want to use VOF modle for thin layer of water that warm from below( marangoni- benard convection ) my qustion: 1- i want to see hexagonal cells in thin layer of water, when i select steady state botton after iteration,when i see my answer, there arent any phase , and all water convert to vapor, how can i do?

2- if it possible , send for me an example near to this situation,thank.

  Reply With Quote


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
VOF Model or Mixture Model mems21 FLUENT 2 March 9, 2010 10:37
A Problem with setting the time step in VOF model Le FLUENT 2 July 20, 2006 22:00
free surface of VOF and melting model? wanghong FLUENT 3 March 13, 2006 09:57
help needed for vof model yan FLUENT 3 December 16, 2005 01:17
Moving mesh or VOF? Giovanni Main CFD Forum 16 September 24, 2001 08:25

All times are GMT -4. The time now is 14:54.