[GaspA]

Hello,
I am trying to calculate the strain rate during the calculation and write it as an ASCII file in the temps folder.
My idea is simply to write the sqrt(2.0)*mag(symm(grad(U))) function in a functionObjects in system/controlDict.
I am using OpenFoam 11.
I took as a basis the example provided with the openfoam.org documentation.
https://cpp.openfoam.org/v11/classFo...ionObject.html


And it works...... No surprises

writeMagU
{

libs ("libutilityFunctionObjects.so");

type coded;
codeWrite
#{

// Lookup U
const volVectorField& U = mesh().lookupObject<volVectorField>("U");
// Write
mag(U)().write();

#};

}

When I try to replace the formula entered, using for example grad(U) or fvc::grad(U) it does not work. Compilation errror "error: ‘fvc’ has not been declared"

What is surprising is that by replacing "codeWrite" with "code", the compilation works but it is impossible to write the file.

Can someone tell me how to integrate the formula sqrt(2.0)*mag(symm(grad(U))) into such a function?

Thank you.

GaspA