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

Simplified VOF Model

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

LinkBack Thread Tools Search this Thread Display Modes
Old   June 10, 2010, 15:57
Default Simplified VOF Model
New Member
Join Date: Jun 2010
Posts: 2
Rep Power: 0
gulbenkian is on a distinguished road

I am trying to solve a transient simplified model in 2D. Air is flowing from a source at 200000 Pa and get into contact with a pool of water of 2mm X 4mm before expands to atmospheric conditions see Figure 1.

I want to see the deformation of the water (droplet formation if any) due to the air flow. I am having problems to get convergence in the model. I am using a VOF model using air as primary phase and the water as secondary phase. As boundary conditions I am using a pressure inlet and pressure oulet conditions. I am patching the water at the beginning. I have used a k-e model and a simplified laminar model for the air and a time step size of 0.0001, however, after I begin the iterative process, it quickly diverge.

I highly appreciate if someone can give me some ideas.

Thanks in advance
gulbenkian is offline   Reply With Quote

Old   June 10, 2010, 16:52
pranab_jha's Avatar
Pranab N Jha
Join Date: Nov 2009
Location: Houston, TX
Posts: 86
Rep Power: 16
pranab_jha is on a distinguished road
What error message does Fluent give you?
I am also using VOF and facing some issues with divergence. I am modeling two-phase flow in pipe. I got the error msg: "divergence detected in AMG solver: pressure correction" when I initialized the whole pipe domain with VF =1 or even with VF = 0.5. But for low phase velocities, I was able to 'avoid' divergence by lowering the relaxation factors for pressure from 1 to 0.5. But I am not able to get around it for higher velocities (air and water ~ 1.5 m/s, pipe dia = 50 mm) by lowering the value further.
I guess you can try it. Maybe it works for you. If you come across any useful tip, do let me know.
pranab_jha is offline   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
Doubts UDS Flux, UDS Unsteady for VOF model kel85uk FLUENT 0 March 17, 2010 08:53
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

All times are GMT -4. The time now is 05:05.