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-   -   Force Coeffs with icoFoam (http://www.cfd-online.com/Forums/openfoam-post-processing/113348-force-coeffs-icofoam.html)

VSass February 18, 2013 11:33

Force Coeffs with icoFoam
 
Hello there,

i'm trying to use the function object forces and forceCoeffs with icoFoam.

i put this in controlDict :

functionObjects
(
forces
{
type forces;
functionObjectLibs ("libforces.so"); //Lib to load
patches (Upstream); // change to your patch name
rhoInf 1.225; //Reference density for fluid
CofR (0.25 0 0); //Origin for moment calculations
}

forceCoeffs
{
type forceCoeffs;
functionObjectLibs ("libforces.so");
patches (Upstream); //change to your patch name
rhoInf 1.225;
CofR (0 0 0);
liftDir (0 1 0);
dragDir (1 0 0);
pitchAxis (0.25 0 0);
magUInf 10.0;
lRef 1;
Aref 1;
}

I thought that a .dat file should appear in my case directory, but nothing happens.
Is there anything else i should do, complie or add something else?

A.Wendy February 19, 2013 03:40

hi,

under your case folder should a folder called "forces" appear where the forces file is stored.

best wishes

Andy

VSass February 19, 2013 06:38

That's the problem, nothing appears. That's why i wonder if i should do some compile or any other form of "activation".

Thanks for the reply

A.Wendy February 19, 2013 06:42

could you post your controlDict and the boundary file?

VSass February 19, 2013 06:45

controlDict

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.1.1 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

application icoFoam;

startFrom startTime;

startTime 0;

stopAt endTime;

endTime 0.5;

deltaT 0.0001;

writeControl timeStep;

writeInterval 50;

purgeWrite 0;

writeFormat ascii;

writePrecision 6;

writeCompression off;

timeFormat general;

timePrecision 6;

runTimeModifiable true;

adjustTimeStep yes;

maxCo 0.5;

functionObjects
(
forces
{
type forces;
functionObjectLibs ("libforces.so"); //Lib to load
patches (Upstream); // change to your patch name
rhoInf 1.225; //Reference density for fluid
CofR (0.25 0 0); //Origin for moment calculations
}

forceCoeffs
{
type forceCoeffs;
functionObjectLibs ("libforces.so");
patches (Upstream); //change to your patch name
rhoInf 1.225;
CofR (0 0 0);
liftDir (0 1 0);
dragDir (1 0 0);
pitchAxis (0.25 0 0);
magUInf 10.0;
lRef 1;
Aref 1;
}
);







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

U boundary

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.1.1 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volVectorField;
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 1 -1 0 0 0 0];

internalField uniform (20 0 0);

boundaryField
{
Downstream
{
type fixedValue;
value uniform (0 0 0);
}

Farfield
{
type inletOutlet;
inletValue uniform (20 0 0);
value uniform (20 0 0);
}

Upstream
{
type fixedValue;
value uniform (0 0 0);
}
}

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

A.Wendy February 19, 2013 06:48

try to put the patch name in your control dict in brackets like:


patches ("Upstream");


regards

Andy

VSass February 19, 2013 07:28

Nothing happens.It just writes down the timesteps folder with u and p but nowhere the forces.

Thanks anyway Andrew, honestly.

A.Wendy February 19, 2013 07:38

try the following:

forces
{
type forces;
functionObjectLibs ("libforces.so"); //Lib to load
outputControl timeStep;
outputInterval 1;
patches ("Upstream"); // change to your patch name
pName p;
UName U;
rhoName rhoInf;
rhoInf 1.225; //Reference density for fluid
log true;
CofR (0.25 0 0); //Origin for moment calculations
}


forceCoeffs
{
type forceCoeffs;
functionObjectLibs ("libforces.so");
outputControl timeStep;
outputInterval 1;
patches ("Upstream"); //change to your patch name
pName p;
UName U;
rhoName rhoInf;
rhoInf 1.225;
CofR (0 0 0);
liftDir (0 1 0);
dragDir (1 0 0);
pitchAxis (0.25 0 0);
magUInf 10.0;
lRef 1;
Aref 1;
log true;
}





i am not sure of the coefficient stuff but the forces should work

VSass February 19, 2013 08:10

Nothing again. I'll give it a shot again later.

Thanks again

A.Wendy February 19, 2013 08:11

strange. can you upload the complete case folder?
i am stuck at another problem and need something new in mind^^


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