[immortality]

here:
http://www.openfoam.org/version2.2.0...processing.php
its mentioned about pressureTools.how can use these function objects?
is there a tutorial or more guidance through?
new pressureTools - enables the calculation of pressure (from kinematic pressure), total pressure, pressure coefficient and total pressure coefficient.

[wyldckat]

Hi Ehsan,

Quick answer:

1. In the following page is a description of the base configurations for function objects: http://foam.sourceforge.net/docs/cpp/a00002.html
2. In this page is the description on how to use the pressure tools: http://foam.sourceforge.net/docs/cpp...8.html#details

Best regards,
Bruno

[immortality]

thank you Bruno
can use a

operation       areaAverage;

with it?
totally can use other features of function objects like the one below with it?
and is there a totalTemperature too or isn't?

Average_left
    {
        type           faceSource;
        functionObjectLibs ("libfieldFunctionObjects.so");
        enabled on;
        log             yes;
        valueOutput     false;
        surfaceFormat   vtk;
        source          patch;
        sourceName      left;
        operation       areaAverage;
        fields
        (
            p
            //phi // surface fields not supported for sampledSurface
            U
            T
            rho
            h
            e
        );
        outputControl timeStep;//outputTime;//
        outputInterval 1; // 5000;
      }

[wyldckat]

Hi Ehsan,

A bit of a confusion of ideas going on here... OK, so to sort out by items:

• Total temperature? I can find anything like that. And temperature in OpenFOAM is usually in Kelvin, so there isn't anything more "total temperature" than the unit that stands for the absolute temperature measurement!
• The function object "pressureTools" must come first in the list of function objects, if you want to use the resulting fields elsewhere.
• The function object "pressureTools" creates volume fields, depending on the calculation. There isn't a direct description, but from the source code, it can create the following field names, depending on the options:
  

  total(p)
  static(p)
  total(p)_coeff
  static(p)_coeff

  These names can be used in the field list for the average function object.

Best regards,
Bruno

[immortality]

you mean I can simply add total(p) to the function as below?without adding anything other?

Average_left
    {
        type           faceSource;
        functionObjectLibs ("libfieldFunctionObjects.so");
        enabled on;
        log             yes;
        valueOutput     false;
        surfaceFormat   vtk;
        source          patch;
        sourceName      left;
        operation       areaAverage;
        fields
        (
            p
            total(p)
            U
            T
            rho
            h
            e
        );
        outputControl timeStep;//outputTime;//
        outputInterval 1; // 5000;
      }

[wyldckat]

Where's the "pressureTools" entry?

I have not tested this, this is just copy-paste-adapt from the pages I posted links for:

    myFunctionObject    // user-defined name of function object entry
    {
        type            pressureTools;
        libs            ("libutilityFunctionObjects.so");
        //region          defaultRegion;
        enabled         yes;
        //timeStart       0;
        //timeEnd         10;
        outputControl timeStep;//outputTime;//
        outputInterval 1; // 5000;
        calcTotal   yes;
        calcCoeff   no;
    }

    Average_left
    {
        type           faceSource;
        functionObjectLibs ("libfieldFunctionObjects.so");
        enabled on;
        log             yes;
        valueOutput     false;
        surfaceFormat   vtk;
        source          patch;
        sourceName      left;
        operation       areaAverage;
        fields
        (
            p
            total(p)
            U
            T
            rho
            h
            e
        );
        outputControl timeStep;//outputTime;//
        outputInterval 1; // 5000;
      }

[immortality]

Ok.thanks.is it true now?

totalP    // user-defined name of function object entry
    {
        type            pressureTools;
        libs            ("libutilityFunctionObjects.so");
        //region          defaultRegion;
        enabled         yes;
        //timeStart       0;
        //timeEnd         10;
        outputControl timeStep;//outputTime;//
        outputInterval 1; // 5000;
        calcTotal   yes;
        calcCoeff   no;
    }

//patch-left------------------------------------------------------------------
    flowInlet
    {
        type swakExpression;
        valueType patch;
        patchName left;
        expression "phi";
        accumulations (
            sum
        );
        verbose true; 
    }

   Average_left
    {
        type           faceSource;
        functionObjectLibs ("libfieldFunctionObjects.so");
        enabled on;
        log             yes;
        valueOutput     false;
        surfaceFormat   vtk;
        source          patch;
        sourceName      left;
        operation       areaAverage;
        fields
        (
            p
            //phi // surface fields not supported for sampledSurface
            U
            T
            rho
            h
            e
        );
        outputControl timeStep;//outputTime;//
        outputInterval 1; // 5000;
      }
      totalPressure_left
    {
        $Average_left;
        operation       weightedAverage;
        weighted rho;
        fields
        (
          total(p)
        );
        outputControl timeStep;//outputTime;//
        outputInterval 1; // 5000;
      }

what was the correct form of this part:

operation       weightedAverage;
        weighted rho;

because I have to use weightedAverage for totalPressure as the link you took me before in another thread.

[wyldckat]

I think it's all OK. I can't see nothing wrong with it.

[immortality]

hi Bruno
Really?i thought maybe those lines for weightedAverarage had another keywords as the case you sent to me before but i can't find now.please have a look into it again tomorrow.
Thanks.
Have a good night.

[wyldckat]

Hi Ehsan,

Sorry, I don't understand the question. The function objects code seems to be OK. I don't see any problem with it.
The reference page on how to use "faceSource" is this one: http://foam.sourceforge.net/docs/cpp...5.html#details

Wait... now I see the problem! It should be:

operation weightedAverage;
weightField rho;

Best regards,
Bruno

[immortality]

Hi
if I want to use function object on a face,how should change these terms?

source          patch;
        sourceName      left;

found it:

source          sampledSurface;
        //sourceName      baffleFaces;
        sampledSurfaceDict
        {
          type cuttingPlane;
          planeType pointAndNormal;
          pointAndNormalDict
          {
             basePoint       (0.0345 0.002 0);
             normalVector    (1 0 0);
          }
          interpolate true;
        }

[immortality]

in compressible case I should use pRef 0;
correct?

[immortality]

it writes total(p) values in all time steps in the solution folder but not in the patch I have set:

# Source : patch left
# Faces  : 60
# Time	sum(magSf)	weightedAverage(total(p))
1.123595506e-08	1.2e-05
2.375195563e-08	1.2e-05
3.694449677e-08	1.2e-05
5.013703791e-08	1.2e-05
6.332957905e-08	1.2e-05
7.652212019e-08	1.2e-05
8.971466133e-08	1.2e-05
1.029072025e-07	1.2e-05
1.160997436e-07	1.2e-05
1.292922847e-07	1.2e-05
1.424848259e-07	1.2e-05
1.55677367e-07	1.2e-05
1.688699082e-07	1.2e-05
1.820624493e-07	1.2e-05
1.952549904e-07	1.2e-05
2.084475316e-07	1.2e-05
2.216400727e-07	1.2e-05
2.348326139e-07	1.2e-05
2.48025155e-07	1.2e-05
2.612176961e-07	1.2e-05
2.744102373e-07	1.2e-05
2.876027784e-07	1.2e-05
3.007953196e-07	1.2e-05
3.110777413e-07	1.2e-05
3.210621219e-07	1.2e-05
3.304918147e-07	1.2e-05
3.395392226e-07	1.2e-05
3.482294959e-07	1.2e-05
3.565855281e-07	1.2e-05
3.64730015e-07	1.2e-05

its the totalP function:

totalP    // user-defined name of function object entry
    {
        type            pressureTools;
        libs            ("libutilityFunctionObjects.so");
        //region          defaultRegion;
        enabled         yes;
        //timeStart       0;
        //timeEnd         10;
        outputControl timeStep;//outputTime;//
        outputInterval 1; // 5000;
        calcTotal   yes;
        calcCoeff   no;
        pRef 0;
    }

and I want on this patch:

totalPressure_left
      {
        $Average_left;
        operation       weightedAverage;
        weightField     rho;
        fields
        (
          total(p)
        );
      }

that its Average_left:

Average_left
    {
        type           faceSource;
        functionObjectLibs ("libfieldFunctionObjects.so");
        enabled on;
        log             yes;
        valueOutput     false;
        surfaceFormat   vtk;
        source          patch;
        sourceName      left;
        operation       areaAverage;
        fields
        (
            p
            //phi // surface fields not supported for sampledSurface
            T
            rho
            h
            U
        );
        outputControl timeStep;//outputTime;//
        outputInterval 1; // 5000;
      }

[wyldckat]

Hi Ehsan,

Took me a while to get to here, but here goes:

1. You told me through an email that if you used swak4Foam, you only needed 1 function instead of 3.
2. Guess what!? swak4Foam 0.2.4 is already available, at least through SVN and at my GitHub account https://github.com/wyldckat/swak4foam (look for the big ZIP button).
   (Side note: Bernhard was at the OFW8 these past days and I think he hasn't had the time to do the final announcements, but he has already provided these news over Twitter.
   ... edit: never mind, he's on top of things : http://www.cfd-online.com/Forums/ope...tml#post433484 post #29)
3. With this version of swak4Foam, which builds without problems with OpenFOAM 2.2.0, the following additional code for the function object should work as expected:
   

   outputControlMode outputTime;
   outputInterval 1;

__________________


As for the original issue on the previous post, I'll quote what I've already sent you through emails - The following function objects worked well together:

functions
{
    writeMissingFields
    {
        type writeRegisteredObject;
        functionObjectLibs ( "libIOFunctionObjects.so" );
        objectNames ("phi");
        outputControl     outputTime;
    }
//................................................................................
    totalP    // user-defined name of function object entry
    {
        type            pressureTools;
        libs            ("libutilityFunctionObjects.so");
        //region          defaultRegion;
        enabled         yes;
        //timeStart       0;
        //timeEnd         10;
        outputControl timeStep;//outputTime;//
        outputInterval 1; // 5000;
        calcTotal   yes;
        calcCoeff   no;
        pRef 0;
    }


    Average_left
    {
        type           faceSource;
        functionObjectLibs ("libfieldFunctionObjects.so");
        enabled on;
        log             yes;
        valueOutput     false;
        surfaceFormat   vtk;
        source          patch;
        sourceName      left;
        operation       areaAverage;
        fields
        (
            p
            //phi // surface fields not supported for sampledSurface
            T
            rho
            h
            U
        );
        outputControl timeStep;//outputTime;//
        outputInterval 1; // 5000;
      }
      reloadTotalP
      {
          type        readFields;
          functionObjectLibs ("libfieldFunctionObjects.so");
          //region          defaultRegion;
          enabled         yes;
          //timeStart       0;
          //timeEnd         10;
          outputControl timeStep;//outputTime;//
          outputInterval 1; // 5000;
          fields
          (
              "total(p)"
          );
      }
      totalPressure_left
      {
        $Average_left;
        operation       weightedAverage;
        weightField     rho;
        
        fields
        (
          total(p)
        );
      }
}

Notes:

• The function object "readFields" was needed for reloading back into memory the field "total(p)".
• As for time folders that only have the field "total(p)": it's because of how the function object was created. It only calculates when it has to write the field to file and it is not registered into memory, which is why we have to use "readFields" for loading it back.
• For this function object to always calculate the field and save it only occasionally, this would require to edit the original source code for the "pressureTools" function object.

Best regards,
Bruno

[immortality]

dear Bruno
it wouldn't make any trouble to use it?because I'm in middle of the run and Bernhard has told maybe it will cause some inconsistency with before versions if I have understood correctly?

[wyldckat]

Originally Posted by immortality

Bernhard has told maybe it will cause some inconsistency with before versions if I have understood correctly?

Are you talking about the following?

Originally Posted by gschaider

- functionObjects now store their data in the sub-directory postProcessing according to the new convention OpenFOAM has (sorry: this may break existing scripts relying on the old location)
- slight change in the format written may break the restart of cases where swak-specific restart data was written with older swak-version (should not hit many people)

Mmm... the first detail isn't very relevant... it's just a matter of moving the folders from the previously generated swak-like folders into the "postProcessing" folder, if I'm not mistaken.
The second detail is likely related to groovyBC!?

[immortality]

thanks.I'm compiling i now.it will replaced to before version automatically?
and I have to move old folders to postProcessing folder manually and no other issue will take place?

[wyldckat]

Originally Posted by immortality

thanks.I'm compiling i now.it will replaced to before version automatically?

Yes, I think so.

Originally Posted by immortality

and I have to move old folders to postProcessing folder manually and no other issue will take place?

Yes, move the ones in the case folder named "swak*". I haven't tested this yet myself, so I'm not 100% sure of this. But from what I briefly saw yesterday from the source code, I think it's all that is necessary.

[BenJ]

Hi Ehsan and Bruno,

I found your post very interesting, since I'm trying to use the pressureTools to compute the static pressure from an incompressible case that uses kinematic pressure.

I would have used the utility as follows:

{
type pressureTools;
libs ("libutilityFunctionObjects.so");
enabled yes;
outputControl timeStep;//outputTime;//
calcTotal no;
calcCoeff no;
}

It does yield a static(p) field, but the values are very low (1e-16).

Have I done something wrong ?

Best regards
BenJ

[GRAUPS]

It does yield a static(p) field, but the values are very low (1e-16).

Ben,

I just figured this out not too long ago. You have to specify a rho value for pressure tools to use to convert from kinematic to static pressure. Add these two lines to your pressure tools functionObject...

rhoName rhoInf;
rhoInf 1.225; // density value

______________________________________

Gentlemen,

I have an additional question related to this pressure tools function object. Is there a way to calculate static pressure for every time step and not have it write out the iteration folder every time step? I want to be able to monitor a mass-weighted static pressure at an outlet every time-step (for an in-compressible solver). I can't find a way to do this though without forcing pressure tools to write an iteration folder every time step. Here is my current pressure-tools setup...

    p_tools
    {
        type                pressureTools;
        functionObjectLibs  ("libutilityFunctionObjects.so");        
        enabled             yes;        
        outputControl       timeStep;
        outputInterval      1; 
        rhoName              rhoInf;
        rhoInf              831.1;
        calcTotal           no;
        calcCoeff           no;
    }

Thanks for any help you guys can provide!

Brock