[giano]

Hi everyone, I am trying to calculate the Shear rate, defined as the square root of the double dot product of the strain-rate tensor with itself. In order to do so I added the following lines of code to the createFields.H of the solver I am currently using:

Info<< "Reading field strainRate\n" << endl;
volScalarField strainRate
(
    IOobject
    (
        "strainRate",
        runTime.timeName(),
        mesh,
        IOobject::MUST_READ,
        IOobject::AUTO_WRITE
    ),
    1.41421356237*mag(symm(fvc::grad(U)))
);

The solver can be compiled and it run correctly, but the results of the new function are pratically 0 eveyrwhere. If I explore the folders corresponding to the time steps, what I found in the file is:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  7
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      binary;
    class       volScalarField;
    location    "0.1";
    object      strainRate;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [0 0 -1 0 0 0 0];

internalField   uniform 0;

boundaryField
{
    leftWall
    {
        type            calculated;
        value           uniform 0;
    }
    rightWall
    {
        type            calculated;
        value           uniform 0;
    }
    lowerWall
    {
        type            calculated;
        value           uniform 0;
    }
    atmosphere
    {
        type            calculated;
        value           uniform 0;
    }
    defaultFaces
    {
        type            empty;
    }
}


// ************************************************************************* //

So it basically performs the computation on the initial velocity field (U=0 everywhere).
Can someone help me?


Thanks in advance.