ersPointSource::ersPointSource
(
    const word& name,
    const dictionary& dict,
    const fvPatch& p
)
:
    ersConstantFlux(name),
    qmax_(readScalar(dict.lookup("qmax"))),
    alpha_(readScalar(dict.lookup("alpha"))),
    direction_(dict.lookup("direction"))
{
    q() = -alpha_*qmax_*min(direction_ & p.Sf()/p.magSf(), 0.0);
}