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

inlet boundary condition based on specified water level

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

Reply
 
LinkBack Thread Tools Display Modes
Old   August 28, 2013, 16:37
Default inlet boundary condition based on specified water level
  #1
Member
 
Hale
Join Date: May 2013
Posts: 53
Rep Power: 3
Hale is on a distinguished road
Hi,

I am dealing with a two phase flow problem where I need to specify a constant water level for the inlet. I do not want to do it by specifying a velocity or flux.

I tried to do it by specifying a hydrostatic pressure (rho*g*h) for p_rgh and zeroGradient for U but it blows up!

Is there any way to specify the height of the water at the inlet?

Thanks
Hale
Hale is offline   Reply With Quote

Old   August 29, 2013, 15:30
Default
  #2
Senior Member
 
Nima Sam
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,092
Blog Entries: 1
Rep Power: 14
nimasam is on a distinguished road
Send a message via Yahoo to nimasam
well i guess you can do it via non-uniform alpha1 (i assumed you use interFoam as solver )
__________________
Training Course on OpenFOAM at (http://www.isme.ir/)
My Weblog (http://openfoam.blogfa.com/)
nimasam is online now   Reply With Quote

Old   August 30, 2013, 04:53
Default
  #3
Member
 
Hale
Join Date: May 2013
Posts: 53
Rep Power: 3
Hale is on a distinguished road
Quote:
Originally Posted by nimasam View Post
well i guess you can do it via non-uniform alpha1 (i assumed you use interFoam as solver )
Hi Nima,

Thanks for the reply. Yes, I use interFoam. For the inlet where I need a constant water level I have defined alpha1=1 and zeroGradient for everwhere else. What did you mean with non-uniform alpha1?
Hale is offline   Reply With Quote

Old   August 30, 2013, 05:05
Default
  #4
Senior Member
 
Nima Sam
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,092
Blog Entries: 1
Rep Power: 14
nimasam is on a distinguished road
Send a message via Yahoo to nimasam
well you can put a non-uniform alpha
something similar this :
Quote:
y < h ? 1 : 0
where h is water level

you can used:

1- code stream
2: groovyBC

to create such nonuniform BC
__________________
Training Course on OpenFOAM at (http://www.isme.ir/)
My Weblog (http://openfoam.blogfa.com/)
nimasam is online now   Reply With Quote

Old   August 30, 2013, 05:16
Default
  #5
Member
 
Hale
Join Date: May 2013
Posts: 53
Rep Power: 3
Hale is on a distinguished road
This is too complicated for me but would you please explain what will this non-uniform alpha1 do? I need a uniform water level at the inlet so why should I changed alpha1 to non-uniform?
Hale is offline   Reply With Quote

Old   August 30, 2013, 05:41
Default
  #6
Senior Member
 
Nima Sam
Join Date: Sep 2009
Location: Tehran, Iran
Posts: 1,092
Blog Entries: 1
Rep Power: 14
nimasam is on a distinguished road
Send a message via Yahoo to nimasam
in your post #1, you said you want a constant water level!, so i assumed! a portion of your inlet fill with water! if the whole inlet is water! then specify the velocity or flux whats wrong then?
__________________
Training Course on OpenFOAM at (http://www.isme.ir/)
My Weblog (http://openfoam.blogfa.com/)
nimasam is online now   Reply With Quote

Old   August 30, 2013, 10:52
Default
  #7
Member
 
Hale
Join Date: May 2013
Posts: 53
Rep Power: 3
Hale is on a distinguished road
The problem is that I'm simulating a real life problem where the flux is not known but the water level can be adjusted. Therefore I want to specify the water level in terms of hydrostatic pressure or something else that can allow the model to find the flux/velocity by itself.
Hale is offline   Reply With Quote

Old   April 10, 2014, 12:18
Default Different water levels; BCs OpenFOAM
  #8
New Member
 
Join Date: Apr 2014
Posts: 1
Rep Power: 0
Sim81 is on a distinguished road
I have a similar problem. I have two water tanks connected by a pipe. The tanks have two different water levels. I want to keep this difference constant but I do not know the flow rate at the inlet and outlet. Therefore I should find the BCs that allows me to keep the water levels constant in the tanks. Any help?

Thank you
Sim81 is offline   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
Low Mixing time Problem Mavier CFX 5 April 29, 2013 01:00
Time dependant pressure boundary condition yosuke1984 OpenFOAM Verification & Validation 2 April 7, 2013 11:36
Boundary layer in a pipe Clementhuon OpenFOAM Native Meshers: snappyHexMesh and Others 6 March 12, 2012 14:41
Velocity inlet boundary condition for porous medium Chander CFX 3 March 11, 2012 23:18
Help for setting 3D boundary condition in compressing water vapor sogolf FLUENT 0 September 27, 2009 16:05


All times are GMT -4. The time now is 14:59.