static Evaluation twoPhaseSatKrnInv(const Params ¶ms, const Evaluation& krn)
{
typedef MathToolbox<Evaluation> Toolbox;
// since inverting the formula for krn is hard to do analytically, we use the
// Newton-Raphson method
Evaluation Sw = Toolbox::createConstant(0.5);
Scalar eps = 1e-10;
for (int i = 0; i < 20; ++i) {
Evaluation f = krn - twoPhaseSatKrn(params, Sw);
Evaluation fStar = krn - twoPhaseSatKrn(params, Sw + eps);
Evaluation fPrime = (fStar - f)/eps;
Evaluation delta = f/fPrime;
Sw -= delta;
if (Sw < 0)
Sw = Toolbox::createConstant(0.0);
if (Toolbox::abs(delta) < 1e-10)
return Sw;
}
OPM_THROW(NumericalIssue,
"Couldn't invert the Brooks-Corey non-wetting phase"
" relperm within 20 iterations");
}
static Evaluation krn(const Params& params, const FluidState& fs)
{
const Evaluation& Sw =
1.0 - Opm::decay<Evaluation>(fs.saturation(Traits::nonWettingPhaseIdx));
return twoPhaseSatKrn(params, Sw);
}
static Evaluation krn(const Params ¶ms, const FluidState &fs)
{
typedef MathToolbox<typename FluidState::Scalar> FsToolbox;
const Evaluation& Sw =
1.0 - FsToolbox::template toLhs<Evaluation>(fs.saturation(Traits::nonWettingPhaseIdx));
return twoPhaseSatKrn(params, Sw);
}
static Evaluation twoPhaseSatKrnInv(const Params& params, const Evaluation& krn)
{
// since inverting the formula for krn is hard to do analytically, we use the
// Newton-Raphson method
Evaluation Sw = 0.5;
Scalar eps = 1e-10;
for (int i = 0; i < 20; ++i) {
Evaluation f = krn - twoPhaseSatKrn(params, Sw);
Evaluation fStar = krn - twoPhaseSatKrn(params, Sw + eps);
Evaluation fPrime = (fStar - f)/eps;
Evaluation delta = f/fPrime;
Sw -= delta;
if (Sw < 0)
Sw = 0.0;
if (Opm::abs(delta) < 1e-10)
return Sw;
}
throw NumericalIssue("Couldn't invert the Brooks-Corey non-wetting phase"
" relperm within 20 iterations");
}
