RelPermUdell.cpp

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// SPDX-FileCopyrightText: Copyright (c) OpenGeoSys Community (opengeosys.org)
// SPDX-License-Identifier: BSD-3-Clause
 
#include "RelPermUdell.h"
 
#include <algorithm>
#include <cmath>
 
#include "MaterialLib/MPL/Medium.h"
 
namespace MaterialPropertyLib
{
RelPermUdell::RelPermUdell(std::string name,
                           const double residual_liquid_saturation,
                           const double residual_gas_saturation,
                           const double min_relative_permeability)
    : residual_liquid_saturation_(residual_liquid_saturation),
      residual_gas_saturation_(residual_gas_saturation),
      min_relative_permeability_(min_relative_permeability)
{
    name_ = std::move(name);
}
 
PropertyDataType RelPermUdell::value(
    VariableArray const& variable_array,
    ParameterLib::SpatialPosition const& /*pos*/, double const /*t*/,
    double const /*dt*/) const
{
    const double S_L = variable_array.liquid_saturation;
 
    if (std::isnan(S_L))
    {
        OGS_FATAL("Liquid saturation not set in RelPermUdell::value().");
    }
 
    auto const S_L_res = residual_liquid_saturation_;
    auto const S_L_max = 1. - residual_gas_saturation_;
 
    auto const S_e = (S_L - S_L_res) / (S_L_max - S_L_res);
 
    if (S_e >= 1.0)
    {
        // fully saturated medium
        return 1.0;
    }
    if (S_e <= 0.0)
    {
        // dry medium
        return min_relative_permeability_;
    }
 
    return std::max(min_relative_permeability_, S_e * S_e * S_e);
}
PropertyDataType RelPermUdell::dValue(
    VariableArray const& variable_array, Variable const variable,
    ParameterLib::SpatialPosition const& /*pos*/, double const /*t*/,
    double const /*dt*/) const
{
    if (variable != Variable::liquid_saturation)
    {
        OGS_FATAL(
            "RelPermUdell::dValue is implemented for derivatives with respect "
            "to liquid saturation only.");
    }
 
    const double S_L = variable_array.liquid_saturation;
 
    auto const S_L_res = residual_liquid_saturation_;
    auto const S_L_max = 1. - residual_gas_saturation_;
    auto const S_e = (S_L - S_L_res) / (S_L_max - S_L_res);
 
    if ((S_e < 0.) || (S_e > 1.))
    {
        return 0.;
    }
 
    auto const dS_e_dS_L = 1. / (S_L_max - S_L_res);
 
    auto const dk_rel_LR_dS_e = 3. * S_e * S_e;
    return dk_rel_LR_dS_e * dS_e_dS_L;
}
 
}  // namespace MaterialPropertyLib