CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Running, Solving & CFD

turbulence boundary condition in groovyBC.

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

Reply
 
LinkBack Thread Tools Display Modes
Old   December 27, 2012, 06:51
Default turbulence boundary condition in groovyBC.
  #1
Senior Member
 
immortality's Avatar
 
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,186
Rep Power: 16
immortality is on a distinguished road
how is it possible to use a variable with time boundary condition for turbulancy in groovyBC?
i want to apply a boundary condition for k and omega in kOmega turbulency model so that it varies between kqrwallfunction for wall and a fixedvalue for environment.how can i enter kqrwallfunction when the patch is wall?
How can i do it?
Any idea and thoght is appreciated and is thanked.
immortality is offline   Reply With Quote

Old   January 5, 2013, 18:51
Default
  #2
Assistant Moderator
 
Bernhard Gschaider
Join Date: Mar 2009
Posts: 3,915
Rep Power: 40
gschaider will become famous soon enoughgschaider will become famous soon enough
Quote:
Originally Posted by immortality View Post
how is it possible to use a variable with time boundary condition for turbulancy in groovyBC?
i want to apply a boundary condition for k and omega in kOmega turbulency model so that it varies between kqrwallfunction for wall and a fixedvalue for environment.how can i enter kqrwallfunction when the patch is wall?
How can i do it?
Any idea and thoght is appreciated and is thanked.
You want a wall function that varies with time? Although this contradicts the later part.

Please do the following: imagine you're another person and don't know what you want to do, then reread you posting and think what you (the you that wrote the posting) wanted to ask ... probably then you'll feel the urge to reformulate the question
__________________
Note: I don't use "Friend"-feature on this forum out of principle. Ah. And by the way: I'm not on Facebook either. So don't be offended if I don't accept your invitation/friend request
gschaider is offline   Reply With Quote

Old   January 6, 2013, 03:27
Default
  #3
Senior Member
 
immortality's Avatar
 
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,186
Rep Power: 16
immortality is on a distinguished road
hi.as i told it should be modeled a changing with time turbulent BC.
As it mentioned there is a patch that changes between a wall and inflow or outflow(like shock tube but left wall is rotating and have some ports in it to the outside environment)i want to use kOmegaSST model.for example for k value in this model there is a submodel for wall named kqRWallFunction.then as i want to use groovyBC i should write the formula of that manually in groovyBC.my question is this.how to write kOmegaSST formula in groovyBC?what are the formula i should use for instance how to write kqRWallFunction?can i write it directly in groovyBC?
I hope this is clear.thanks.
immortality is offline   Reply With Quote

Old   January 6, 2013, 06:56
Default
  #4
Assistant Moderator
 
Bernhard Gschaider
Join Date: Mar 2009
Posts: 3,915
Rep Power: 40
gschaider will become famous soon enoughgschaider will become famous soon enough
Quote:
Originally Posted by immortality View Post
hi.as i told it should be modeled a changing with time turbulent BC.
As it mentioned there is a patch that changes between a wall and inflow or outflow(like shock tube but left wall is rotating and have some ports in it to the outside environment)i want to use kOmegaSST model.for example for k value in this model there is a submodel for wall named kqRWallFunction.then as i want to use groovyBC i should write the formula of that manually in groovyBC.my question is this.how to write kOmegaSST formula in groovyBC?what are the formula i should use for instance how to write kqRWallFunction?can i write it directly in groovyBC?
I hope this is clear.thanks.
OK. Now you're getting clearer.

If you look at the implementation of kqRWallFunction it says in the comment "Boundary condition for turbulence k, Q, and R when using wall functions. Simply acts as a zero gradient condition." so by switching the fractionExpression to 0 and having the gradientExpression 0 as well should give you what you want
__________________
Note: I don't use "Friend"-feature on this forum out of principle. Ah. And by the way: I'm not on Facebook either. So don't be offended if I don't accept your invitation/friend request
gschaider is offline   Reply With Quote

Old   January 6, 2013, 09:32
Default
  #5
Senior Member
 
immortality's Avatar
 
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,186
Rep Power: 16
immortality is on a distinguished road
thanks.you mean in folders k,Q and R i should set them as zeroGradient when the patch is wall in fact.right?but I don't know what are k,Q and R and I haven't a folder named Q in my case.also I have deleted R folder because in parallel run an error has occured and referred to the R function and as I asked at another thread someone replied that I have no need in R folder in kOmegaSST model.please explain a little more.thanks.
immortality is offline   Reply With Quote

Old   January 6, 2013, 16:00
Default
  #6
Assistant Moderator
 
Bernhard Gschaider
Join Date: Mar 2009
Posts: 3,915
Rep Power: 40
gschaider will become famous soon enoughgschaider will become famous soon enough
Quote:
Originally Posted by immortality View Post
thanks.you mean in folders k,Q and R i should set them as zeroGradient when the patch is wall in fact.right?but I don't know what are k,Q and R and I haven't a folder named Q in my case.also I have deleted R folder because in parallel run an error has occured and referred to the R function and as I asked at another thread someone replied that I have no need in R folder in kOmegaSST model.please explain a little more.thanks.
Q and r are calculated. You don't have to specify them
__________________
Note: I don't use "Friend"-feature on this forum out of principle. Ah. And by the way: I'm not on Facebook either. So don't be offended if I don't accept your invitation/friend request
gschaider is offline   Reply With Quote

Old   January 7, 2013, 04:19
Default
  #7
Senior Member
 
immortality's Avatar
 
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,186
Rep Power: 16
immortality is on a distinguished road
thanks.for only knowing im curious about what can be q and r?is r refered to reynolds stress?
Then i should only set k to 0 in gradientExpression and value at inlet?
immortality 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
Boundary condition with a non-uniform gradient - groovyBC? STiss OpenFOAM Programming & Development 3 October 11, 2013 02:04
inlet velocity boundary condition murali CFX 5 August 3, 2012 08:56
asking for Boundary condition in FLUENT Destry FLUENT 0 July 27, 2010 00:55
Turbulence Model Boundary Condition sanxian FLUENT 1 December 23, 2006 14:01


All times are GMT -4. The time now is 00:01.