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

Unsteady boundary condition for temperatureenergy

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 18, 2007, 21:52
Default Hello, Thanks to the answer
  #1
New Member
 
Kian Mehravaran
Join Date: Mar 2009
Location: London, U.K
Posts: 22
Rep Power: 17
kian is on a distinguished road
Hello,

Thanks to the answers to another user's question, I was able
to implement unsteady boundary conditions in "sonicFoam" by
changing the boundary values in the code itself.

The variables I want to change at the boundaries are velocity
and temperature. There are no problems with velocity.
However, since the solver solves for internal energy, I need
to modify the boundary value for internal energy, as changing
temperature alone would not be correct.

This is not a problem for this case. However, I am planning to
have unsteady boundary conditions on reacting cases, with multiple
species, and I was wondering if there is a more elegant way to
do this?

Would using the "timeVaryingUniformFixedValue" type for the
boundary conditions solve this problem?
I tried to use it based on the answer given to another question,
but I get this error:

BICCG: Solving for Ux, Initial residual = 1, Final residual = 1.10364e-16, No Iterations 1


--> FOAM FATAL IO ERROR : file "" does not exist

file: at line 1.

From function IFstream::operator()
in file db/IOstreams/Fstreams/IFstream.C at line 160.


Thank you for your help,

Kian
kian is offline   Reply With Quote

Old   September 19, 2007, 02:58
Default Hi Kian, I assume you are u
  #2
New Member
 
Masato Otsuki
Join Date: Mar 2009
Location: Tokyo, Japan
Posts: 26
Rep Power: 17
otsuki is on a distinguished road
Hi Kian,

I assume you are using OpenFOAM-1.4 or 1.4.1.
You need specify filename in boundaryField.
An example for T field is as follows:
===
boundaryField
{
inlet
{
type timeVaryingUniformFixedValue;
timeDataFileName "inletTemp";
value uniform 315;
}
}
===
File "inletTemp" must be placed in "<root>" or
the filename must include relative path from
<root> when you execute "sonicFoam <root> <case>".

Masato
otsuki is offline   Reply With Quote

Old   September 19, 2007, 11:02
Default Hi Masato, Thanks for your
  #3
New Member
 
Kian Mehravaran
Join Date: Mar 2009
Location: London, U.K
Posts: 22
Rep Power: 17
kian is on a distinguished road
Hi Masato,

Thanks for your help, but this is exactly what I did, except that I am on 1.3.1. Could this be the problem?

Thanks,

Kian
kian is offline   Reply With Quote

Old   September 20, 2007, 01:42
Default Hello again, I was trying t
  #4
New Member
 
Kian Mehravaran
Join Date: Mar 2009
Location: London, U.K
Posts: 22
Rep Power: 17
kian is on a distinguished road
Hello again,

I was trying to avoid 1.4.1, but I compiled the source, and I still get the same error:

file "" does not exist

Any suggestions?

thanks,

Kian
kian is offline   Reply With Quote

Old   September 20, 2007, 02:06
Default Hi, Kian Sorry, this is not
  #5
New Member
 
Masato Otsuki
Join Date: Mar 2009
Location: Tokyo, Japan
Posts: 26
Rep Power: 17
otsuki is on a distinguished road
Hi, Kian

Sorry, this is not a problem with versions.
For OF-1.3 and OF-1.4, I confirmed your problem
with sonicFoam & timeVarying..BC for T.

I found timevarying..BC works for
sonicTurbFoam using h.
In sonicTurbFoam, h is a data member of
basicThermo class. And basicThermo
calcualates h from T or T from h.
I guess timeVarying..BC for T works for another
applications using basicThermo class or derived
class of it.
otsuki is offline   Reply With Quote

Old   September 20, 2007, 17:07
Default Hello Masato, Thank you for
  #6
New Member
 
Kian Mehravaran
Join Date: Mar 2009
Location: London, U.K
Posts: 22
Rep Power: 17
kian is on a distinguished road
Hello Masato,

Thank you for you help, sonicTurbFoam does what I'm looking for.About the timeVaryingUniformFixedValue, I have found out that in sonicFoam, I can use it with the pressure boundary condition with no problems. However, when I do the same with temperature, I get this,

FOAM FATAL IO ERROR : file "" does not exist
, which looks like it does not read the file name in the temperature boundary condition.

Just curious.

Thanks,

Kian Mehravaran
kian is offline   Reply With Quote

Old   September 20, 2007, 23:23
Default Hi Kian, Explaining the dif
  #7
New Member
 
Masato Otsuki
Join Date: Mar 2009
Location: Tokyo, Japan
Posts: 26
Rep Power: 17
otsuki is on a distinguished road
Hi Kian,

Explaining the different effect of
timeVaryingUniformFixedValue BC on T
for sonicFoam and sonicTurbFoam
( e=cv*T and thermo->h() ) is beyond
my understanding of FOAM.

I hope someone else will explain why.

Bests,
Masato
otsuki is offline   Reply With Quote

Reply


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
Convective outlet boundary condition for Unsteady flows msrinath80 OpenFOAM Running, Solving & CFD 109 November 28, 2016 11:53
Initial condition for unsteady calculation Jianglan Main CFD Forum 4 October 6, 2008 00:55
Boundary condition of the third kind or Danckwertz boundary condition plage OpenFOAM Running, Solving & CFD 4 October 3, 2006 13:21
Periodic boundary condition & Unsteady flow Somchai FLUENT 2 March 28, 2006 09:51
Unsteady mass-flow rate boundary condition Leon FLUENT 0 October 20, 2004 07:29


All times are GMT -4. The time now is 12:30.