CFD Online Discussion Forums - How to calculate and write out transient drag / lift coefficient in OpenFOAM 2.2.1?

CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)

- OpenFOAM (https://www.cfd-online.com/Forums/openfoam/)

- - How to calculate and write out transient drag / lift coefficient in OpenFOAM 2.2.1? (https://www.cfd-online.com/Forums/openfoam/125113-how-calculate-write-out-transient-drag-lift-coefficient-openfoam-2-2-1-a.html)

How to calculate and write out transient drag / lift coefficient in OpenFOAM 2.2.1?

It seems that a keyword functions containing forces and forcesCoeffs should be added at the end of controlDict.

Is there any tutorial to give a typical example, and what's the meaning of each entry.

These two are founded on OpenFOAM forum.

Code:

functions

{ forces

{

type forceCoeffs;

functionObjectLibs ( "libforces.so" );

outputControl timeStep;

outputInterval 1;

patches (profile_wall)

pName p;

UName U;

log true;

rhoInf 1.225;

CofR ( 0 0 0 );

liftDir ( 0 1 0 );

dragDir (1 0 0 );

pitchAxis ( 0 0 1 );

magUInf 100.0;

lRef 0.1254;

Aref 0.01292;

}

}

Code:

functions

{

forces

{

type forces;

functionObjectLibs ( "libforces.so" ); // lib to load

outputControl timeStep;

outputInterval 1;

patches

(

wall // change to your patch name

);

// name of fields

pName p;

UName U;

log true; // dump to file

rhoInf 1025;

CofR ( 0 0 0 );

}

forcesCoeffs

{

type forceCoeffs;

functionObjectLibs ( "libforces.so" ); // lib to load

outputControl timeStep;

outputInterval 1;

patches

(

wall // change to your patch name

);

// name of fields

pName p;

UName U;

log true; // dump to file

rhoInf 1025;

CofR ( 0 0 0 );

liftDir ( 0 1 0 );

dragDir ( 1 0 0 );

pitchAxis ( 0 0 0 );

magUInf 7.30;

lRef 0.305;

Aref 0.001525;

}

}

Thanks in advance.

there is not any difference between the steady and unsteady case
it is sufficient to add as follow

Code:

forcesCoeffs { type forceCoeffs; functionObjectLibs ( "libforces.so" ); // lib to load outputControl timeStep; outputInterval 1; patches ( wall // change to your patch name ); // name of fields pName p; UName U; log true; // dump to file rhoInf 1025; CofR ( 0 0 0 ); liftDir ( 0 1 0 ); dragDir ( 1 0 0 ); pitchAxis ( 0 0 0 ); magUInf 7.30; lRef 0.305; Aref 0.001525; } }