foam-extend4.1-coherent-io/applications/solvers/immersedBoundary/interIbFoam/limitU.H

{
    scalar limitMagU =
        readScalar(mesh.solutionDict().subDict("PIMPLE").lookup("limitMagU"));

    volScalarField magU(mag(U));

    scalar maxMagU = max(magU).value();

    Info<< "mag(U): max: " << maxMagU
        << " avg: " << magU.weightedAverage(mesh.V()).value();

    if (maxMagU > limitMagU)
    {
        U.internalField() *=
            neg(magU.internalField() - limitMagU)
          + pos(magU.internalField() - limitMagU)*
            limitMagU/(magU.internalField() + SMALL);
        U.correctBoundaryConditions();
        Info << " ...limiting" << endl;
    }
    else
    {
        Info << endl;
    }
}