[jcw]

Hello!


I am using OF4.1. I am struggeling with the evaluation of total pressure at patches named "IN" and "OUT". I was able to calculate the total pressure field. But I have no idea how to extract the mass-flow weighted total pressure at my boundary patches.


Solver: simpleFoam


controlDict:
.
.
runTimeModifiable true;

functions
{
#includeFunc flowRatePatch(name=IN)
#includeFunc flowRatePatch(name=OUT)
#includeFunc residuals

pressure1
{
type pressure;
libs ("libfieldFunctionObjects.so");
patches (IN);
writeControl timeStep;
writeInterval 1;
log on;
pRef 1;
// Calculate the total pressure
calcTotal yes; // yes | no

// Calculate the (total) pressure coefficient
calcCoeff no; // yes | no
}
}



BTW:
The flowRatePatches evaluation work perfect. And I would like to have total pressure value each for "IN" and "OUT".


Thanks for support!

[jcw]

No ideas? Are there information missing?

[akidess]

This works with OF-5.0:

pIN
{   
        type            surfaceFieldValue;
        functionObjectLibs ("libfieldFunctionObjects.so");

        writeFields     false;
        writeControl    timeStep;
        writeInterval   1;  

        // Output to log&file (true) or to file only
        log             true;
        valueOutput     true;
        source          patch;
        sourceName      "IN";

        regionType      patch;
        name            "IN";
        surfaceFormat   ensight;

        // Operation: areaAverage/sum/weightedAverage ... 
        operation       areaAverage;

        fields
        (
            p
        );
     }

[jcw]

Thanks! I works. I had to change 'type surfaceFieldValue' -> 'type surfaceRegion'. Then it can be used for OP4.1.


How can I evaluate the total pressure at patch called 'IN'? Changing the 'fields' to total(p) is not working:

pIN
{
type surfaceRegion;
functionObjectLibs ("libfieldFunctionObjects.so");

writeFields false;
writeControl timeStep;
writeInterval 1;

// Output to log&file (true) or to file only
log true;
valueOutput true;
source patch;
sourceName "IN";

regionType patch;
name "IN";
surfaceFormat ensight;

// Operation: areaAverage/sum/weightedAverage ...
operation areaAverage;

fields
(
total(p)
);
}

gives the following error:

Time = 1

smoothSolver: Solving for Ux, Initial residual = 1, Final residual = 0.0903489, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 1, Final residual = 0.0335626, No Iterations 3
smoothSolver: Solving for Uz, Initial residual = 1, Final residual = 0.0335636, No Iterations 3
GAMG: Solving for p, Initial residual = 1, Final residual = 0.0331327, No Iterations 7
time step continuity errors : sum local = 0.00124111, global = 0.000336422, cumulative = 0.000336422
smoothSolver: Solving for omega, Initial residual = 0.158845, Final residual = 0.00888191, No Iterations 2
smoothSolver: Solving for k, Initial residual = 1, Final residual = 0.0486494, No Iterations 2
ExecutionTime = 7.84 s ClockTime = 8 s

surfaceRegion pIN write:
--> FOAM Warning :
From function virtual bool Foam::functionObjects::fieldValues::surfaceRegion: :write()
in file fieldValues/surfaceRegion/surfaceRegion.C at line 780
Requested field total(p) not found in database and not processed

And also important: Where can I find information on how to use the post-processing tools?

[akidess]

You can't do in-situ postprocessing of the total pressure, because it is not available by default. Easiest solution is to compute the total pressure and the samples in post after the simulation has completed.

Your first stop for information on how to use the postprocessing tools is the openfoam manual.

[jcw]

Here is my ./system/controlDict file to get relevant data during simulation. Maybe it helps other users with same problem.
It works well for OF4.1 and simpleFoam.

 functions
    {
    #includeFunc flowRatePatch(name=IN)
    #includeFunc flowRatePatch(name=OUT)
    #includeFunc residuals
        #includeFunc totalPressureIncompressible
    #includeFunc pressureDifferencePatch
    #includeFunc singleGraph
    #includeFunc surfaces
    #includeFunc streamlines

yPlus1
    {
    type    yPlus;
    libs ("libfieldFunctionObjects.so");
    result WALL;
    executeControl    writeTime;
    writeControl    writeTime;
    }


pressureTools1
    {
        type                pressure;
        functionObjectLibs ("libutilityFunctionObjects.so");
        enabled             yes;
        //region              0;
        calcTotal           yes;
        calcCoeff           no;
        timeStart           1;
        timeEnd             100000;
        writeControl        outputTime;
        writeInterval       1;
    pRef            0;
        rhoInf              1.17663;
        pInf                101325;
        UInf                (0 0 0);
     }


reloadPcalc
    {
        type        readFields;
        functionObjectLibs ("libfieldFunctionObjects.so");
        //region          0;
        enabled         yes;
        timeStart       1;
        timeEnd         10000;
        writeControl    writeTime;
        writeInterval    1;
        outputInterval 1; // 5000;
        fields
        (
        total(p)
        p
        
        );
    }


outlet_avg_p
    {
        

        type            surfaceRegion;
        libs            ("libfieldFunctionObjects.so");
    enabled         true;
        log             true;
    valueOutput     false;
        timeStart       1;
        writeControl    timeStep;
        writeInterval    1;
        writeFields     off;
        regionType      patch;
        name            OUT;
    surfaceFormat   none;
        operation       areaAverage;        
        fields
        (
           // total(p)
    p
        );
    }


outlet_avg_ptot
    {
         

        type            surfaceRegion;
    libs         ("libfieldFunctionObjects.so");
        enabled         true;
        log             true;
        valueOutput     false;
                   timeStart    1;
                writeControl    timeStep;
                writeInterval   1;
        writeFields     off;
        regionType    patch;
        name            OUT;
        surfaceFormat   none;
        operation    areaAverage;
        fields
    (
        total(p)
        //p
        );
    }

inlet_avg_p
    {


         type            surfaceRegion;
        libs            ("libfieldFunctionObjects.so");
        enabled         true;
        log             true;
        valueOutput     false;
                timeStart    1;
                writeControl    timeStep;
                writeInterval   1;
        writeFields     off;
        regionType    patch;
        name            IN;
        surfaceFormat   none;
        operation    areaAverage;
        fields
    (
           // total(p)
        p
    );
    }


inlet_avg_ptot
    {


        type            surfaceRegion;
        libs            ("libfieldFunctionObjects.so");
        enabled         true;
        log             true;
        valueOutput     false;
                timeStart    1;
                   writeControl    timeStep;
                   writeInterval   1;
        writeFields     off;
        regionType      patch;
        name            IN;
        surfaceFormat   none;
    operation    areaAverage;
        fields
        (
        total(p)
        //p
        );

Files needed in ./system directory:

controlDict
decomposeParDict
fvSolution
topoSetDict
fvSchemes
pressureDifferencePatch
residuals
singleGraph
streamlines
surfaces
 yPlus

Regards.