[kcengiz]

Hi all,
I am trying to calculate the force on an immersed boundary, where an unsteady case is considered (channel flow DNS). Instead of running the simulation for a sufficient time and getting the average of the forces, I wanted to use my available field pMean & UMean that I collected before. as i changed the function object entry in my controlDict as below

    

forces
    {
        type               immersedBoundaryForces;
        functionObjectLibs ("libimmersedBoundaryForceFunctionObject.so");

        outputControl timeStep;
        outputInterval 1;
        patches ( IB );

        pName       pMean;
        UName       UMean;
        rhoName     rhoInf;
        rhoInf      1;

        log         true;
        CofR        ( 0 0 0 );

        Aref 0.05;
        Uref 1;
    }

Interestingly, the viscous forces happened to be (0,0,0) whereas using instantaneous flow (with p & U) had yielded plausible results. I don't see a reason why the mean flow should yield (0,0,0) viscous force. Can you?


A side question: Is there a way in foam-extend-4.0 to run this immersedBoundaryForce as a standalone postprocessing tool? That is, without running the simulation (the function object way), as done using postProcess in OpenFoam?


Thank you very much! Keep safe and healthy..
Cengiz