[CFDelix]

Hi All,

I am wondering if it is possible to use the swak4Foam functionality for an already finished simulation.

I defined this Testfunction in my controlDict:

functions
{
    Testfunction
    {
        type swakExpression;
        valueType patch;
        patchName interface_name;
        outputControlMode outputTime;
        variables
        (
             "Profil=sum(sqrt(pow(U.x*area(),2)+pow(U.y*area(),2)+pow((U.z-4.5129)*area(),2)))/sum(area());"
        );
        accumulations ( average );
        expression "Profil";
        verbose true;
        writeStartTime no;
        autoInterpolate true;
        warnAutoInterpolate false;
        outputInterval 5000;
    }    
}

It works while the simulation in running (for outputControlMode timeStep and outputInterval 1).

Now I want to change the "Profil"-function and since I am only interested in the converged solution I only need to evaluate the function for my last timestep (5000).

1) Is there a way I can use the postProcess utility with swak4foam?

postProcess -fields '(U p)' -time 5000

results in no errors and creates a postProcessing/swakExpression_Testfunction/5000 folder which contains an empty file.

2) Is there a way I can use the sample utility with swak4foam?

When I create a sampleDict with the function "Testfunction" (+ adding "libs ("libsampling.so");") and use

postProcess -func sampleDict

I get this error

keyword type is undefined in dictionary ".functions.sampleDict"

3) I might have totally misunderstood the postProcess utility since for a different function

    Testfunction2
    {
        type expressionField;
        outputInterval 5000;
  pName p;
  Uname U;
        variables
        (
             "BM=0;"
             "XM=pos().x+BM;"
             "thetaAngle=(XM!=0) ? acos(XM/sqrt(pow(XM,2)+pow(pos().y,2)))*pos().y/mag(pos().y) : ((pos().y>0) ? 0 : 3.1416);"
        );
        fieldName Test;
        dimension [0 1 -1 0 0 0 0];
        expression "-U.x*sin(thetaAngle)+U.y*cos(thetaAngle)";
        autowrite true;
    }

is resulting in another error

Parser Error for driver FieldValueExpressionDriver at "1.2" :"field U not existing or of wrong type"

Thanks for your replies!

[CFDelix]

Seems like I didn't read enough before asking...

Maybe it is still usefull to somebody else :

The funkyDoCalc utility does exactly what I was looking for.
Thanks to: http://openfoamwiki.net/images/2/2a/...esentation.pdf (page 111) and https://www.cfd-online.com/Forums/op...nkydocalc.html


Create a i.e. "postDict" (file like

Testfunction
    {
        type swakExpression;
        valueType patch;
        patchName interface_name;
        variables
        (
             "Profil=sum(sqrt(pow(U.x*area(),2)+pow(U.y*area(),2)+pow((U.z-4.5129)*area(),2)))/sum(area());"
        );
        accumulations ( average );
        expression "Profil";
        verbose true;
        writeStartTime no;
        autoInterpolate true;
        warnAutoInterpolate false;
        autowrite true;
    }

and then execute

funkyDoCalc -time 5000: postDict -writeCsv

I am still not sure why expressionFields are not evaluated by this method.

And I am still confused why the "postProcess" utility isn't doing the same jobs. In the post I mentioned above the "execFlowFunctionObjects" command is described as doing nearly the same, but for my OF version (2.0) it says that

execFlowFunctionObjects has been superseded by the '-postProcess' solver command-line option, e.g.
simpleFoam -help -postProcess

so I couldn't test it.

Not all questions answered, but that is all I need for my case at the moment.

[CFDelix]

I found a solution for my problems by the funkyDoCalc command. I probably just didn't search long enough, but maybe this helps someone else.

Solution:
http://openfoamwiki.net/images/2/2a/...esentation.pdf (page 111)

https://www.cfd-online.com/Forums/op...nkydocalc.html

I created a "postDict" file

Testfunction
{
        type swakExpression;
        valueType patch;
        patchName interface_name;        
        variables
        (
             "Profil=sum(sqrt(pow(U.x*area(),2)+pow(U.y*area(),2)+pow((U.z-4.5129)*area(),2)))/sum(area());"
        );
        accumulations ( average );
        expression "Profil";
        verbose true;
        writeStartTime no;
        autoInterpolate true;
        warnAutoInterpolate false;
        autowrite true;
}

and executed

funkyDoCalc -time 5000: postDict -writeCsv

Open questions:

I am still confused why the funkyDoCalc isn't working for expressionsFields.

I still don't understand the postProcess utilty. In the post that I mentioned above, the execFlowFunctionObjects is described and that it might help.
Problem is that in my OpenFOAM (Version 2.0) the execFlowFunctionObjects command give:

execFlowFunctionObjects has been superseded by the '-postProcess' solver command-line option, e.g.
simpleFoam -help -postProcess

My problems are solved for the moment. Hopefully it is also usefull to you!

[miha23]

Dear Felix.

It happened, that I'm having the same issue as you, trying to use swak4Foam functions after simulation.
But in my case I am trying to use the swakExpressionAverageDistribution function.
Have you got any idea how it should look like?

What I tried this far is the following:

Function
{
type swakExpressionAverageDistribution;
libs (
"libOpenFOAM.so"
"libsimpleSwakFunctionObjects.so"
"libswakFunctionObjects.so"
"libgroovyBC.so"
);

writeStartTime no;
valueType internalField;
expression "T";
verbose true;
weight "vol()";
mask "1";
abscissa "pos().z";
dynamicExtremesAbscissa false;
minAbscissa 0;
maxAbscissa 150;
binNumber 75;
valueIfZero 0;
accumulations ( average );

}

But this turned out with an error messege which I can not solve:

--> FOAM FATAL ERROR:
The expected return type bool is different from the stored result type "scalar"



From function tmp<Field<Type> > ExpressionResult::getResult()
in file ../../Libraries/swak4FoamParsers/lnInclude/ExpressionResultI.H at line 250.

FOAM exiting

Thanks,

Gábor

[CFDelix]

The postDict file needs to be in the main (simulation) folder not within your system folder. (So that it is on the same folder level as your system folder.)

Maybe that will solve your problem.

Otherwise it would be helpful if you post your PostDict file and your folderstructure.

[miha23]

Thanks Felix.
I have solved that problem succesfully, but on the meantime I edited the question above for an other problem which is now actual.
I would be thankfull is you could take a look at that.

Thanks,
Gábor

[CFDelix]

I haven't used swakExpressionAverageDistribution myself so I am not sure how to use it correctly.

I get the same error though.
Maybe you could use swakExpression and define your own "expression" for the averaging operation you want to do.

[CFDelix]

Ok apparently the "mask "1";" is causing trouble.

averagePressureDistributionX {
 type swakExpressionAverageDistribution;
 verbose true;
 outputControlMode outputTime;
 valueType internalField;
 expression "p";
 weight "vol()";
 mask "p<1";
 abscissa "pos().x";
 binNumber 50;
 valueIfZero -100;
 accumulations ( max );
}

this example returns a value for my case

[miha23]

I applied what you have suggested, and luckily I also got something as a result.
It seems like process, but as I see it correct, it is an average (or max/min) of the whole domain, and what is needed, is a list of these averages at different i.e "pos().z".
It seems like it do not handle this part:

abscissa "pos().z";
dynamicExtremesAbscissa false;
minAbscissa 0;
maxAbscissa 150;
binNumber 10;

Have you got any idea?

[CFDelix]

Since I am not familiar with swakExpressionAverageDistribution I would change the example I mentioned above for different surfaces.

You should check some examples (i.e. https://github.com/wyldckat/swak4foa...stCalculations)
One example for a surface plane:

 
surfacePlane{type swakExpression;valueType surface;surfaceName testPlane;surface {type plane;basePoint (0 0 0);normalVector (0 0 1);interpolate false;}verbose true;expression "mag(U)";accumulations (minmax);

You just need to change the expression to the average that you want to calculate, i.e.:

expression "sum(p*area())/sum(area())";

[Bodo1993]

Originally Posted by miha23

I applied what you have suggested, and luckily I also got something as a result.
It seems like process, but as I see it correct, it is an average (or max/min) of the whole domain, and what is needed, is a list of these averages at different i.e "pos().z".
It seems like it do not handle this part:

abscissa "pos().z";
dynamicExtremesAbscissa false;
minAbscissa 0;
maxAbscissa 150;
binNumber 10;

Have you got any idea?

Hi, I am wondering if you were able to resolve the issue (i.e. to output "a list of the averages at different i.e "pos().z"."). Thanks

[ErenC]

Umm, is it possible to use funkyDoCalc for all* timeSteps? My simulation stopped due to power outage and when I restart simulation (dumb mistake, it started from timeStep 1) all my postProcess data overwriten. And It is really pain to do 1020(timesteps) "funkyDoCalc". When I use "noZero" for time, it gaves me same values for all timeSteps...

Time = 570

local :  weightedAverage=30.85399601
bulk :  weightedAverage=301.8301434


Time = 575

local:  weightedAverage=30.85399601
bulk :  weightedAverage=301.8301434

[ErenC]

I also happened to realise when I use

funkyDoCalc -time '5,10,20' avgs

I get:

Time = 5
fraction : swak4Foam: Setting default mesh
swak4Foam: Allocating new repository for sampledMeshes
swak4Foam: Allocating new repository for sampledGlobalVariables
 average=0.01949977306


Time = 10
fraction :  average=0.01949977306


Time = 20
fraction :  average=0.01949977306

End

And it makes no sense to me. Those values should not be same obviously.

[ErenC]

@gschaider I still couldnt fix the problem in last entry. Could it be a bug for OF2006? (also -time 5:600 is giving me same values for all timesteps)

[gschaider]

Originally Posted by ErenC

@gschaider I still couldnt fix the problem in last entry. Could it be a bug for OF2006? (also -time 5:600 is giving me same values for all timesteps)

Seems that the part that loads the new fields seems to be broken again



I'll have a look but don't hold your breath (end-of-year project rush etc)

[ErenC]

Originally Posted by gschaider

Seems that the part that loads the new fields seems to be broken again



I'll have a look but don't hold your breath (end-of-year project rush etc)

Thank you! I'll be waiting in patience.