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

Boundary Condition

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

Reply
 
LinkBack Thread Tools Display Modes
Old   April 15, 2005, 10:59
Default Hello, I tried to use "pres
  #1
Member
 
Join Date: Mar 2009
Posts: 43
Rep Power: 8
vatant is on a distinguished road
Hello,
I tried to use "pressureTransmissive" boundary condition with lInf specified. however, when i ran my code : it said ,

FOAM FATAL IO ERROR : keyword lInf is undefined in dictionary "/run/tutorials/../0/p:: Outlet"

..
Function:dictionary :: lookupEntry (const word& keyword) const
in file : db/dicitonary/dictionary.C at line : 148

I dont know how to fix this. Should i include any extra lib files in /make/options ?


Thanks


Vatant
vatant is offline   Reply With Quote

Old   April 15, 2005, 11:14
Default It sounds like you have made a
  #2
Senior Member
 
Join Date: Mar 2009
Posts: 854
Rep Power: 13
henry is on a distinguished road
It sounds like you have made a mistake in way you have added the lInf entry.
henry is offline   Reply With Quote

Old   April 15, 2005, 11:39
Default In the /case/0/p file bound
  #3
Member
 
Join Date: Mar 2009
Posts: 43
Rep Power: 8
vatant is on a distinguished road
In the /case/0/p file

boundaryField
{
Outlet
{
type pressureTransmissive;
pInf 1e5;
lInf 0.5;
}
.
.
}

etc

I did not use pressureTransmissive type patch in the mesh i imported frm fluent.

Do you think, I need to add the pressure type patch anywhere else ?

Thanks

Vatant
vatant is offline   Reply With Quote

Old   April 15, 2005, 14:52
Default Dr.Weller, I tried to u
  #4
Member
 
Join Date: Mar 2009
Posts: 43
Rep Power: 8
vatant is on a distinguished road
Dr.Weller,

I tried to use zeroGradient for velocity at outlet and this error disappeared. However, I have an compressible flow scenario and hence my rho field reads:

{
Inlet
(
type inletOutlet;
inletValue 920;
)
Outlet
(
type inletOutlet;
inletValue 900;
)
.
.
.
.
}

I tried using this condition using OpenFoam 1.0 and Foam Exited.

I am not sure how to handle the pressuretransmissive nature using Foam...

in my case, i have an totalpressure in a tank with an exit nozzle where pressuretransmissive is required due to reflective boundary nature.

( a compressible laminar liquid flow)


My velocity at inlet is 'pressureinletoutletvelocity' calculated using the total pressure ..and at outlet ..i guess..zerogradient is appropriate due to pressuretransmissive nature.

the domain is initially with water everywhere..and hence i used,

{
inlet
(
type inletOutlet;
inletValue ...
)
...
...

and at the Outlet..i tried different combinations

)

I had earlier run with constant pressure outlet (fixed value) but the solution easily showed boundary reflection.

Could you help me handle the boundary conditions ?

Thanks


Vatant
vatant is offline   Reply With Quote

Old   April 15, 2005, 17:38
Default The pressureTransmissive press
  #5
Senior Member
 
Join Date: Mar 2009
Posts: 854
Rep Power: 13
henry is on a distinguished road
The pressureTransmissive pressure BC is currently written for gases not liquids, if you need a version for liquids you will have to write a version for yourself based on the one I wrote for gases.
henry is offline   Reply With Quote

Old   April 15, 2005, 18:20
Default Thanks Dr.Weller. Where can i
  #6
Member
 
Join Date: Mar 2009
Posts: 43
Rep Power: 8
vatant is on a distinguished road
Thanks Dr.Weller. Where can i find pressureTransmissive BC module for gases so that I can try and set one up for liquids.


Vatant
vatant is offline   Reply With Quote

Old   April 17, 2005, 07:20
Default You will find the source code
  #7
Senior Member
 
Join Date: Mar 2009
Posts: 854
Rep Power: 13
henry is on a distinguished road
You will find the source code for all the physical boundary conditions in OpenFOAM-1.1/src/OpenFOAM/fields/fvPatchFields/derivedFvPatchFields
henry is offline   Reply With Quote

Old   April 18, 2005, 09:30
Default How can i include the required
  #8
Member
 
Join Date: Mar 2009
Posts: 43
Rep Power: 8
vatant is on a distinguished road
How can i include the required boundary conditions patch fields to my /username/applications ?

I have the required p0, rho0,psi for calculation in pressureTransmissive ..does it require any other parameter ? I guess the p0 is the boundary outlet pressure itself ..with rho0 = rho(t=0) given.

With these where should i place my fields file *.C and *.H for my application ?

Thanks


VATANT
vatant is offline   Reply With Quote

Old   April 19, 2005, 19:06
Default Dr.Weller, I modified onl
  #9
Member
 
Join Date: Mar 2009
Posts: 43
Rep Power: 8
vatant is on a distinguished road
Dr.Weller,

I modified only the p0, rho0 and PSI for pressureTransmissive to read. Does this condition work differently for gas and liquids or can i jus use different p0, rho0 and PSI (for liquids) ?

In the pressureTransmissive conditions, wht if lInf = 0 does it imply completely non-reflective conditions ( I guess this is Navier Stokes Characteristic Boundary Condition NSCBC's)

Also, If my actual boundary value (pressure exit ) is say Pexit, does Pinf in pressureTransmissive same as Pexit ? (if it was a fixedValue pressureOutlet) ?


Thanks


Vatant
vatant is offline   Reply With Quote

Old   September 19, 2005, 15:58
Default I patch a value of a field in
  #10
Member
 
olivier Petit
Join Date: Mar 2009
Location: Göteborg, Sweden
Posts: 67
Rep Power: 8
olivier is on a distinguished road
I patch a value of a field in a wall boundary at each iteration.
what is the type which I should associate to this boundary, knowing that zeroGradient generate a false segmentation after the 4th iteration.
thanks a lot
olivier is offline   Reply With Quote

Old   September 20, 2005, 12:49
Default can some one help me please th
  #11
Member
 
olivier Petit
Join Date: Mar 2009
Location: Göteborg, Sweden
Posts: 67
Rep Power: 8
olivier is on a distinguished road
can some one help me please thank you
I patch a value of a field in a wall boundary at each iteration.
what is the type which I should associate to this boundary, knowing that zeroGradient generate a false segmentation after the 4th iteration.
olivier is offline   Reply With Quote

Old   September 20, 2005, 13:10
Default I dont understand what you mea
  #12
Senior Member
 
Eugene de Villiers
Join Date: Mar 2009
Posts: 725
Rep Power: 12
eugene is on a distinguished road
I dont understand what you mean. If you are altering the boundary value, it clearly cant be zeroGradient. What are you doing and why are you doing it?
eugene is offline   Reply With Quote

Old   September 20, 2005, 17:36
Default Hi Eugene I have two zones of
  #13
Member
 
olivier Petit
Join Date: Mar 2009
Location: Göteborg, Sweden
Posts: 67
Rep Power: 8
olivier is on a distinguished road
Hi Eugene
I have two zones of calculation, over these zones I resolve different equations.

potential vector values obtained in the inferior wall (buttom) of the 1st zone must be patched in the walls superior wall (top) of the 2nd zone.

what is the type which I should associate to this boundary (superior and inferior wall).
thanks a lot
olivier is offline   Reply With Quote

Old   September 21, 2005, 04:06
Default I guess something like bott
  #14
Super Moderator
 
Mattijs Janssens
Join Date: Mar 2009
Posts: 1,416
Rep Power: 16
mattijs is on a distinguished road
I guess something like

bottom: zerogradient (i.e. extrapolated from the internal values)or better inletOutlet.
top: fixedValue
mattijs is offline   Reply With Quote

Old   August 28, 2006, 10:48
Default Hello, Could someone give m
  #15
New Member
 
Jeff Allen
Join Date: Mar 2009
Posts: 11
Rep Power: 8
jballen is on a distinguished road
Hello,

Could someone give me an example of using the findNearestBoundaryFace function, given a coordinate location.

Thanks,
Jeff
jballen 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 for UDS Tomik FLUENT 0 December 5, 2006 18:37
Boundary condition of the third kind or Danckwertz boundary condition plage OpenFOAM Running, Solving & CFD 4 October 3, 2006 12:21
Slip Boundary Condition for Moving Boundary Shukla Main CFD Forum 3 November 11, 2005 16:02
UDF boundary condition Jeff FLUENT 2 November 20, 2003 18:15
Boundary Condition in LES Zhang Tsiang Main CFD Forum 3 February 5, 2002 21:15


All times are GMT -4. The time now is 05:09.