[shuoxue]

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.

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;
}
}

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.

[mechy]

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

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; } }