[levoCFD]

Hi everyone,

I am working on a multiphase simulation with multiphaseEulerFoam and I would like to use OpenFOAM's post-processing function forceCoeffs.
I am calling it in the controlDict like:

forceCoeffs
    {
        type forceCoeffs;
        functionObjectLibs ("libforces.so");
        patches (walls);
        rhoInf 1.225;
        CofR (0.25 0 0);
        liftDir (0 1 0);
        dragDir (1 0 0);
        pitchAxis (0 0 1);
        magUInf 10.0;
        lRef 1;
         Aref 0.01;


         rho rhoInf;
        U U.gas;
     }

I am getting the following error message:

--> FOAM FATAL ERROR: 
No valid model for viscous stress calculation

I checked the source code to find out where the error is generated (l. 277 in functionObjects/forces/forces/forces.C). To avoid the error I have tried adding a transportProperties file with the following content:

transportModel  Newtonian;
rho             [1 -3 0 0 0 0 0] 1;
nu              [0 2 -1 0 0 0 0] 1e-05;

However, this did not solve the issue. Has anyone successfully used forceCoeffs in combination with multiphaseEulerFoam or could give me a hint on how to make them work together?

[yuming_shao]

Originally Posted by levoCFD

Hi everyone,

I am working on a multiphase simulation with multiphaseEulerFoam and I would like to use OpenFOAM's post-processing function forceCoeffs.
I am calling it in the controlDict like:

forceCoeffs
    {
        type forceCoeffs;
        functionObjectLibs ("libforces.so");
        patches (walls);
        rhoInf 1.225;
        CofR (0.25 0 0);
        liftDir (0 1 0);
        dragDir (1 0 0);
        pitchAxis (0 0 1);
        magUInf 10.0;
        lRef 1;
         Aref 0.01;


         rho rhoInf;
        U U.gas;
     }

I am getting the following error message:

--> FOAM FATAL ERROR: 
No valid model for viscous stress calculation

I checked the source code to find out where the error is generated (l. 277 in functionObjects/forces/forces/forces.C). To avoid the error I have tried adding a transportProperties file with the following content:

transportModel  Newtonian;
rho             [1 -3 0 0 0 0 0] 1;
nu              [0 2 -1 0 0 0 0] 1e-05;

However, this did not solve the issue. Has anyone successfully used forceCoeffs in combination with multiphaseEulerFoam or could give me a hint on how to make them work together?

I have the same problem. Have you solved it? And this is two-fluid, nu values need to be mixed.

[levoCFD]

Originally Posted by yuming_shao

I have the same problem. Have you solved it? And this is two-fluid, nu values need to be mixed.

No, unfortunately I have not. I ended up using a Lagrangian solver, anyway. That is why I did not have to deal with this any further.