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

Error using GroobyBC

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 30, 2010, 10:58
Default Error using GroobyBC
  #1
New Member
 
Join Date: Aug 2010
Posts: 14
Rep Power: 15
NewFoamer is on a distinguished road
Hello,

I'm trying to use GroovyBC to implement following boundary on the velocity field:

PHP Code:
feed
    
{
        
type            groovyBC;
        
variables       "pFeed@feed=p;pDraw@draw=p;";
        
valueExpression "(pFeed-pDraw)*normal()";
        
value           uniform (0 0 0);        
    }

    
draw
    
{
        
type            fixedValue;
        
variables       "pFeed@feed=p;pDraw@draw=p;";
        
valueExpression "(pFeed-pDraw)*normal()";
        
value           uniform (0 0 0);        
    } 
However, when trying to use icoFoam to solve my problem, I get following error:

PHP Code:
Courant Number mean0 max2e-05
DILUPBiCG
:  Solving for UxInitial residual 1, Final residual 3.1531e-07No Iterations 4
DILUPBiCG
:  Solving for UyInitial residual 0, Final residual 0No Iterations 0
DICPCG
:  Solving for pInitial residual 1, Final residual 9.95444e-07No Iterations 257
time step continuity errors 
sum local 2.58366e-13, global = 9.29505e-16cumulative 9.29505e-16
--> FOAM Warning 
    
From function PatchResult::getUniformInternal(const label size,bool noWarn)
    
in file PatchResultI.H at line 96
    The minimum value 53.321 
and the maximum 1346.83 differI will use the average 687.19
DICPCG
:  Solving for pInitial residual 0.999897, Final residual 8.51967e-07No Iterations 260
time step continuity errors 
sum local 8.51066e-09, global = 1.06309e-11cumulative 1.06318e-11
--> FOAM Warning 
    
From function PatchResult::getUniformInternal(const label size,bool noWarn)
    
in file PatchResultI.H at line 96
    The minimum value 
-2.21757e+09 and the maximum -3.40424e+08 differI will use the average -1.63456e+09
ExecutionTime 
1.1 s  ClockTime 1 s 
Is it that I cannot access the pressure fields in this way, or why is it happening?
NewFoamer is offline   Reply With Quote

Old   August 30, 2010, 12:48
Default
  #2
Assistant Moderator
 
Bernhard Gschaider
Join Date: Mar 2009
Posts: 4,225
Rep Power: 51
gschaider will become famous soon enoughgschaider will become famous soon enough
Quote:
Originally Posted by NewFoamer View Post
Hello,

I'm trying to use GroovyBC to implement following boundary on the velocity field:

PHP Code:
feed
    
{
        
type            groovyBC;
        
variables       "pFeed@feed=p;pDraw@draw=p;";
        
valueExpression "(pFeed-pDraw)*normal()";
        
value           uniform (0 0 0);        
    } 
However, when trying to use icoFoam to solve my problem, I get following error:

PHP Code:
--> FOAM Warning 
    
From function PatchResult::getUniformInternal(const label size,bool noWarn)
    
in file PatchResultI.H at line 96
    The minimum value 53.321 
and the maximum 1346.83 differI will use the average 687.19 
Is it that I cannot access the pressure fields in this way, or why is it happening?
The problem is that feed and draw (for instance) may have differing numbers of faces. What would be the correct way to map pDraw to feed then? Therefor groovyBC only uses uniform values for external variables. If the variable is not uniform (as in your case) groovyBC decides to make it uniform and instead of keeping you in the dark about this decision tells you about it.

To avoid the warning you'll have to "uniformize" p with either min, max, sum or average.

Even if feed and draw are of the same size there is no guarantee that the faces there are orderered the same (and what means "the same" anyway if they are not oriented in parallel) so groovyBC even then makes no attempt to use non-uniform values. So if you wanted to use groovyBC to generate some cyclic-BC: sorry. Not possible at the time

Bernhard
gschaider is offline   Reply With Quote

Old   August 30, 2010, 12:56
Default
  #3
New Member
 
Join Date: Aug 2010
Posts: 14
Rep Power: 15
NewFoamer is on a distinguished road
Ah, okay, awesome, thanks for the answer..
NewFoamer is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On



All times are GMT -4. The time now is 00:43.