[usv001]

Originally Posted by ari003

Your post was very helpful but I ve another issue. I ve seen that the number of velocity should match with the number of faces but I m getting the output velocity as equal to the number of points(which is not the face center value). I m using OF7 which doesnt have sampledict folder. Is there any way by which I can get the output velocity corresponding to the face center?

Hi ari003,

I am assuming that you are trying to sample the patch values. The sampling process is different in the newer version. The following worked for me:

1. Place a file caled 'singleGraph' in the system/ directory
   

   /*--------------------------------*- C++ -*----------------------------------*\
   | =========                 |                                                 |
   | \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
   |  \\    /   O peration     | Version:  v1906                                 |
   |   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
   |    \\/     M anipulation  |                                                 |
   \*---------------------------------------------------------------------------*/
   FoamFile
   {
       version     2.0;
       format      ascii;
       class       dictionary;
       location    "system";
       object      singleGraph;
   }
   // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
   
   singleGraph
   {
       type            surfaces;
       libs            ("libsampling.so");
       writeControl    writeTime;
   
       fields          ( rho );
       surfaceFormat   boundaryData;
       surfaces
       (
           right_patch
           {
               type            patch;
               patches         ("right"); // patch names
               interpolate     false;
           }
       );
   }
   
   // ************************************************************************* //

2. Run the command 'postProcess -func singleGraph'

The sampled patch values will be generated in the correct format in the postProcessing/singleGraph/ directory.

Cheers,
USV

[ari003]

/*--------------------------------*- C++ -*----------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Version: 7
\\/ M anipulation |
-------------------------------------------------------------------------------
Description
Writes graph data for specified fields along a line, specified by start
and end points.

\*---------------------------------------------------------------------------*/

start (0 1e-06 0);
end (1 1e-06 0);
fields (U p);

// Sampling and I/O settings
#includeEtc "caseDicts/postProcessing/graphs/sampleDict.cfg"

// Override settings here, e.g.
/*
setConfig
{
type lineCell;
axis x; // y, z, xyz
}
*/

// Must be last entry
#includeEtc "caseDicts/postProcessing/graphs/graph.cfg"

// ************************************************** *********************** //

It is giving the value along a line and the singleGraph folder looks like this which is quite different from yours.

[usv001]

Originally Posted by ari003

/*--------------------------------*- C++ -*----------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Version: 7
\\/ M anipulation |
-------------------------------------------------------------------------------
Description
Writes graph data for specified fields along a line, specified by start
and end points.

\*---------------------------------------------------------------------------*/

start (0 1e-06 0);
end (1 1e-06 0);
fields (U p);

// Sampling and I/O settings
#includeEtc "caseDicts/postProcessing/graphs/sampleDict.cfg"

// Override settings here, e.g.
/*
setConfig
{
type lineCell;
axis x; // y, z, xyz
}
*/

// Must be last entry
#includeEtc "caseDicts/postProcessing/graphs/graph.cfg"

// ************************************************** *********************** //

It is giving the value along a line and the singleGraph folder looks like this which is quite different from yours.

This is the default file. Create a new file 'singleGraph' in the system/ directory and copy the contents from my previous post.

USV

[ari003]

--> FOAM FATAL IO ERROR:
keyword interpolationScheme is undefined in dictionary "controlDict.functions.singleGraph.singleGraph "

file: controlDict.functions.singleGraph.singleGraph from line 20 to line 34.

From function const Foam::entry& Foam::dictionary::lookupEntry(const Foam::word&, bool, bool) const
in file db/dictionary/dictionary.C at line 573.

When I run the command it is showing up this error. What can I do any idea?

[usv001]

Originally Posted by ari003

--> FOAM FATAL IO ERROR:
keyword interpolationScheme is undefined in dictionary "controlDict.functions.singleGraph.singleGraph "

file: controlDict.functions.singleGraph.singleGraph from line 20 to line 34.

From function const Foam::entry& Foam::dictionary::lookupEntry(const Foam::word&, bool, bool) const
in file db/dictionary/dictionary.C at line 573.

When I run the command it is showing up this error. What can I do any idea?

Whenever I face such a problem, I include the missing keyword ('interpolationScheme' in this case) in the dictionary with some dummy entry.

singleGraph
{
    ...
    interpolationScheme blah; // blah = some dummy value
    ...
}

OpenFOAM will throw an error saying that the entry 'blah' is invalid and will give you a list of valid entries. Choose one that works.

USV

[ari003]

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v1906 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object singleGraph;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

singleGraph
{
type surfaces;
libs ("libsampling.so");
writeControl writeTime;
interpolationScheme blah;

fields ( U );
surfaceFormat boundaryData;
surfaces
(
right_patch
{
type patch;
patches ("right"); // patch names
interpolate true;
}
);
}

// ************************************************** *********************** //

I used cell, cellPoint, blah but now it is not showing up in the post-processor directory. Even when I used blah it didnt pop up any error.

[usv001]

Originally Posted by ari003

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v1906 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object singleGraph;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

singleGraph
{
type surfaces;
libs ("libsampling.so");
writeControl writeTime;
interpolationScheme blah;

fields ( U );
surfaceFormat boundaryData;
surfaces
(
right_patch
{
type patch;
patches ("right"); // patch names
interpolate true;
}
);
}

// ************************************************** *********************** //

I used cell, cellPoint, blah but now it is not showing up in the post-processor directory. Even when I used blah it didnt pop up any error.

What I provided earlier worked for me in v1906. I am not sure if it will work in v7. In v1906, it did not ask for interpolationScheme also.

By the way, do you have a patch named 'right'? If not, please try using one of your patches.

USV

[ari003]

Sir, actually I was trying to extract one surface from the pitzdaily case and feed that output velocity into the inlet. I did that by using surface dict and that gave the velocity at all points i.e 62 velocities but I want the velocity corresponding to the faces i.e 30 velocity component so that I can feed that in input. But at this point I m unable to extract the velocity corres to each face at that specific surface. I had put the patch name as"surfaces" still it didnt work and even I cant send you the file because it is exceeding the limit. Any kind of help will be really great.

[usv001]

Originally Posted by ari003

Sir, actually I was trying to extract one surface from the pitzdaily case and feed that output velocity into the inlet. I did that by using surface dict and that gave the velocity at all points i.e 62 velocities but I want the velocity corresponding to the faces i.e 30 velocity component so that I can feed that in input. But at this point I m unable to extract the velocity corres to each face at that specific surface. I had put the patch name as"surfaces" still it didnt work and even I cant send you the file because it is exceeding the limit. Any kind of help will be really great.

Then your patches entry should have the patch name 'outlet'. Also, if you just want the values maybe you can just extract them from the field files using bash commands like sed or awk.

USV

[ari003]

Didnt work also after putting outlet as the name of the patch.