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

Boundary condition of free surface model

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

Reply
 
LinkBack Thread Tools Display Modes
Old   September 26, 2004, 17:04
Default Boundary condition of free surface model
  #1
Tony
Guest
 
Posts: n/a
Dear all,

I use Fluent to model the water ejecting from a small pipe. I tried to use VOF model and define the free surface area as pressure_inlet, but it did not converge. My model has one velocity_inlet, one pressure_inlet and one pressure_outlet. Can anyone recommend the way to help the simulation converged ? I tried to follow all instructions in the manual, but it still not converged.

By the way, I search how to model the free surface and I got three ways to do it as follow :

1. Define the surface as a wall and then put the Shear stresses to 0 for x and y.

2. Define the surface with symmetry boundary condition.

3. Use VOF model and set the surface as a pressure inlet.

Can anyone explain the differences between these boundary conditions ? or recommend which way is good for the water jet ?

Thank you for your kind attention.

Tony
  Reply With Quote

Old   September 26, 2004, 18:14
Default Re: Boundary condition of free surface model
  #2
Aravind
Guest
 
Posts: n/a
Hi,

Can you define your problem more specifically? where is your pressure inlet, since your geometry is a pipe, do you mean to say that through one end of your pipe there is water coming in and flowing out through the other end into ambient atmosphere? right?

Aravind
  Reply With Quote

Old   September 27, 2004, 00:45
Default Re: Boundary condition of free surface model
  #3
Tony
Guest
 
Posts: n/a
Hi Aravind,

Thank you very much for your kind attention.

Yes. It likes the water flowing out the pipe to the atmospere. At the flow inlet to the pipe, it is set to be Velocity_Inlet. At the atmosphere, the outlet of the pipe, I set it to Pressure_inlet on the top, while the bottom is symmetry and the other end is Pressure_outlet. Inside the pipe, it has two channels of water combining together before ejecting to the atmosphere. Now I used K-Epsilon for turbulent and VOF for free surface.

Please recommend me how to set the boundary condition. Am I right about the way to set the free surface ? As my first message, what is the difference between the three ways to simulate the free surface ?

Thank you very much in advance for your kindly help.

Sincerely yours,

Tony
  Reply With Quote

Old   September 27, 2004, 13:48
Default Re: Boundary condition of free surface model
  #4
Titiksh Patel
Guest
 
Posts: n/a
Hi,

Can you tell me what is your domain, means what you are modellinn in addition to the pipe inlet.

For eg. a pipe filling a water tank, etc. Its your case is like this one.

I can give more details only after undertandinn your problem

Regards, Titiksh
  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
Import problem ARC Open Source Meshers: Gmsh, Netgen, CGNS, ... 0 February 27, 2010 11:56
MULTIPHASE - FREE SURFACE & MIXTURE MODEL Aris FLUENT 3 April 28, 2009 11:46
Multiphase flow. Dispersed and free surface model Luis CFX 8 May 29, 2007 18:13
boundary condition at free surface mike NUMECA 3 June 8, 2006 06:23
how to define the free surface condition major FLUENT 0 November 3, 2004 01:27


All times are GMT -4. The time now is 01:03.