setRDeltaT.H

{
    volScalarField& rDeltaT = trDeltaT.ref();

    scalar rDeltaTSmoothingCoeff
    (
        runTime.controlDict().getOrDefault<scalar>
        (
            "rDeltaTSmoothingCoeff",
            0.02
        )
    );

    // Set the reciprocal time-step from the local Courant number
    rDeltaT.ref() = max
    (
        1/dimensionedScalar("maxDeltaT", dimTime, maxDeltaT),
        fvc::surfaceSum(amaxSf)()()
       /((2*maxCo)*mesh.V())
    );

    // Update tho boundary values of the reciprocal time-step
    rDeltaT.correctBoundaryConditions();

    fvc::smooth(rDeltaT, rDeltaTSmoothingCoeff);

    Info<< "Flow time scale min/max = "
        << gMin(1/rDeltaT.primitiveField())
        << ", " << gMax(1/rDeltaT.primitiveField()) << endl;
}