thresholdcapillarypressures.hh

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#ifndef DUMUX_PNM_THRESHOLD_CAPILLARY_PRESSURES_HH
#define DUMUX_PNM_THRESHOLD_CAPILLARY_PRESSURES_HH
 
#include <cmath>
 
namespace Dumux::PoreNetwork {
 
struct ThresholdCapillaryPressures
{
    template<class Scalar>
    static constexpr Scalar pcSnapoff(const Scalar surfaceTension,
                                      const Scalar contactAngle,
                                      const Scalar inscribedRadius) noexcept
    {
        using std::sin;
        using std::cos;
        const Scalar theta = contactAngle;
        const Scalar cosTheta = std::cos(theta);
        const Scalar sinTheta = std::sin(theta);
        return surfaceTension / inscribedRadius * (cosTheta - sinTheta);
    }

    template<class Scalar>
    static constexpr Scalar pcEntry(const Scalar surfaceTension,
                                    const Scalar contactAngle,
                                    const Scalar inscribedRadius,
                                    const Scalar shapeFactor) noexcept
    {
        using std::sin;
        using std::cos;
        using std::sqrt;
        const Scalar theta = contactAngle;
        const Scalar cosTheta = cos(theta);
        const Scalar sinTheta = sin(theta);
 
        const Scalar D = M_PI - 3*theta + 3*sinTheta*cosTheta - (cosTheta*cosTheta) / (4*shapeFactor);
        const Scalar F = (1 + sqrt(1 + 4*shapeFactor*D / (cosTheta*cosTheta))) / (1 + 2*sqrt(M_PI*shapeFactor));
        return surfaceTension / inscribedRadius * cosTheta * (1 + 2*sqrt(M_PI*shapeFactor)) * F;
    }
};
 
} // namespace Dumux::PoreNetwork
 
#endif