slipcondition.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_FREEFLOW_NAVIERSTOKES_SLIPCONDITION_HH
#define DUMUX_FREEFLOW_NAVIERSTOKES_SLIPCONDITION_HH
 
#include <dune/common/fvector.hh>
#include <dumux/common/tag.hh>
#include <dumux/common/parameters.hh>
#include <dumux/discretization/method.hh>
 
namespace Dumux::NavierStokes::SlipConditions {
 
struct BJ : public Utility::Tag<BJ> {
    static std::string name() { return "Beavers-Joseph"; }
};
 
struct BJS : public Utility::Tag<BJS> {
    static std::string name() { return "Beavers-Joseph-Saffman"; }
};
 
inline constexpr BJ bj{};
 
inline constexpr BJS bjs{};
 
} // end namespace Dumux::NavierStokes::SlipConditions
 
namespace Dumux {
 
template<class DiscretizationMethod, class SlipCondition>
class NavierStokesSlipVelocity;
 
template<class SlipCondition>
class NavierStokesSlipVelocity<DiscretizationMethods::FCStaggered, SlipCondition>
{
public:
    static constexpr SlipCondition slipCondition{};
 
    template<class Problem, class FVElementGeometry, class ElementVolumeVariables, class Scalar>
    static auto velocity(const Problem& problem,
                           const FVElementGeometry& fvGeometry,
                           const typename FVElementGeometry::SubControlVolumeFace& scvf,
                           const ElementVolumeVariables& elemVolVars,
                           Scalar tangentialVelocityDeriv)
   {
        assert(scvf.isLateral());
        assert(scvf.boundary());
 
        static constexpr int dimWorld = FVElementGeometry::GridGeometry::GridView::dimensionworld;
        using Vector = Dune::FieldVector<Scalar, dimWorld>;
 
        Vector porousMediumVelocity(0.0);
 
        if constexpr (slipCondition == NavierStokes::SlipConditions::bj)
            porousMediumVelocity = problem.porousMediumVelocity(fvGeometry, scvf);
        else if (!(slipCondition == NavierStokes::SlipConditions::bjs))
            DUNE_THROW(Dune::NotImplemented, "Fcstaggered currently only implements BJ or BJS slip conditions");
 
        const auto& scv = fvGeometry.scv(scvf.insideScvIdx());
 
        // create a unit normal vector oriented in positive coordinate direction
        Vector tangent(0.0);
        tangent[scv.dofAxis()] = 1.0;
 
        // du/dy + dv/dx = beta * (u_boundary-uPM)
        // beta = alpha/sqrt(K)
        const Scalar betaBJ = problem.betaBJ(fvGeometry, scvf, tangent);
        const Scalar distanceNormalToBoundary = (scvf.ipGlobal() - scv.dofPosition()).two_norm();
 
        static const bool onlyNormalGradient = getParamFromGroup<bool>(problem.paramGroup(), "FreeFlow.EnableUnsymmetrizedVelocityGradientForBeaversJoseph", false);
        if (onlyNormalGradient)
            tangentialVelocityDeriv = 0.0;
 
        const Scalar scalarSlipVelocity = (tangentialVelocityDeriv*distanceNormalToBoundary
            + porousMediumVelocity * tangent * betaBJ * distanceNormalToBoundary
            + elemVolVars[scv].velocity()) / (betaBJ*distanceNormalToBoundary + 1.0);
 
        return scalarSlipVelocity*tangent;
    }
};
 
} // end namespace Dumux
 
#endif