CFD Online Discussion Forums - How to get forces and forceCoeffs in v2.0.0

Add this to the end of your <case>/system/controlDict file.

Replace patchname with your patches.

Then get your scalar constants sorted out (i.e.: lRef, Aref, magUInf) and vector constants (i.e.: liftDir, dragDir, pitchAxis)

Code:

functions

{

    forces

    {

        type            forceCoeffs;

        functionObjectLibs ( "libforces.so" );

        outputControl   timeStep;

        outputInterval  1;



        patches

        (

            patchname

        );



        pName       p;

        UName       U;

        rhoName            rhoInf;

        

        log         true;

        rhoInf      1.225;

        CofR        ( 0 0 0 );

        liftDir     ( 0 1 0 );

        dragDir     ( 1 0 0 );

        pitchAxis   ( 0 0 0 );

        magUInf     50;

        lRef        1;

        Aref        1;

    }

}

Note: In 2.0.0 (vs 1.7.1) you need to define rhoName as rhoInf, otherwise you will get this error

Code:

--> FOAM Warning : 

    From function void forces::read(const dictionary&)

    in file forces/forces.C at line 277

    Could not find U, p or rho in database.

    De-activating forces.