frictionlaw.hh

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// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// vi: set et ts=4 sw=4 sts=4:
//
// SPDX-FileCopyrightInfo: Copyright © DuMux Project contributors, see AUTHORS.md in root folder
// SPDX-License-Identifier: GPL-3.0-or-later
//
#ifndef DUMUX_MATERIAL_FLUIDMATRIX_FRICTIONLAW_HH
#define DUMUX_MATERIAL_FLUIDMATRIX_FRICTIONLAW_HH
 
#include <algorithm>
#include <cmath>
 
#include <dune/common/fvector.hh>
 
namespace Dumux {
template <typename VolumeVariables >
class FrictionLaw
{
    using Scalar = typename VolumeVariables::PrimaryVariables::value_type;
public:
    virtual Dune::FieldVector<Scalar, 2> bottomShearStress(const VolumeVariables& volVars) const = 0;
 
    Scalar limitRoughH(const Scalar roughnessHeight, const Scalar waterDepth, const Scalar eps=1.0e-12) const
    {
        using std::clamp;
 
        // return zero if the roughness depth is near zero
        if (roughnessHeight < eps) return 0.0;
 
        // calculate the artificial water depth
        const Scalar mobilityMax = 1.0; 
 
        const Scalar minUpperH = roughnessHeight * 2.0;
        const Scalar sw = clamp(waterDepth * (1.0/minUpperH), 0.0, 1.0);
        const Scalar mobility = mobilityMax /(1.0 + (1.0-sw)*(1.0-sw));
        return roughnessHeight * (1.0 - mobility);
    }
 
    // virtual base class needs a virtual destructor
    virtual ~FrictionLaw() = default;
};
 
} // end namespace Dumux
 
#endif