[assembly] introduce fv operators

dumux/assembly/fv/CMakeLists.txt

+install(FILES
+operators.hh
+DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/dumux/assembly/fv)

dumux/assembly/fv/operators.hh

+// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+// vi: set et ts=4 sw=4 sts=4:
+/*****************************************************************************
+ *   See the file COPYING for full copying permissions.                      *
+ *                                                                           *
+ *   This program is free software: you can redistribute it and/or modify    *
+ *   it under the terms of the GNU General Public License as published by    *
+ *   the Free Software Foundation, either version 3 of the License, or       *
+ *   (at your option) any later version.                                     *
+ *                                                                           *
+ *   This program is distributed in the hope that it will be useful,         *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of          *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the            *
+ *   GNU General Public License for more details.                            *
+ *                                                                           *
+ *   You should have received a copy of the GNU General Public License       *
+ *   along with this program.  If not, see <http://www.gnu.org/licenses/>.   *
+ *****************************************************************************/
+/*!
+ * \file
+ * \ingroup Assembly
+ * \brief The base class for the sub-control entity-local evaluation of
+ *        the terms of equations in the context of finite-volume schemes
+ */
+#ifndef DUMUX_FV_OPERATORS_HH
+#define DUMUX_FV_OPERATORS_HH
+
+#include <dumux/common/numeqvector.hh>
+#include <dumux/discretization/extrusion.hh>
+
+namespace Dumux::Experimental {
+
+/*!
+ * \ingroup Assembly
+ * \brief The base class for the sub-control entity-local evaluation of
+ *        the terms of equations in the context of finite-volume schemes
+ * \tparam LC the element-stencil-local data required to evaluate the terms
+ */
+template<class LC>
+class FVOperators
+{
+    // The grid geometry on which the scheme operates
+    using FVElementGeometry = typename LC::ElementGridGeometry;
+    using GridGeometry = typename FVElementGeometry::GridGeometry;
+    using SubControlVolume = typename GridGeometry::SubControlVolume;
+    using SubControlVolumeFace = typename GridGeometry::SubControlVolumeFace;
+    using Extrusion = Extrusion_t<GridGeometry>;
+
+    // The variables (primary/secondary) on the grid
+    using GridVariables = typename LC::ElementVariables::GridVariables;
+    using PrimaryVariables = typename GridVariables::PrimaryVariables;
+
+public:
+    //! export the local context on which this operates
+    using LocalContext = LC;
+
+    //! export the type used to store scalar values for all equations
+    using NumEqVector = Dumux::NumEqVector<PrimaryVariables>;
+
+    // export the types of the flux/source/storage terms
+    using FluxTerm = NumEqVector;
+    using SourceTerm = NumEqVector;
+    using StorageTerm = NumEqVector;
+
+    /*!
+     * \name Model specific interfaces
+     * \note The following method are the model specific implementations of the
+     *       operators appearing in the equation and should be overloaded by the
+     *       implementations.
+     */
+    // \{
+
+    /*!
+     * \brief Compute the storage term of the equations for the given sub-control volume
+     * \param problem The problem to be solved (could store additionally required quantities)
+     * \param context The element-stencil-local required data
+     * \param scv The sub-control volume
+     * \note This must be overloaded by the implementation
+     */
+     template<class Problem>
+     static StorageTerm storage(const Problem& problem,
+                                const LocalContext& context,
+                                const SubControlVolume& scv)
+    { DUNE_THROW(Dune::NotImplemented, "Storage operator not implemented!"); }
+
+    /*!
+     * \brief Compute the flux term of the equations for the given sub-control volume face
+     * \param problem The problem to be solved (could store additionally required quantities)
+     * \param context The element-stencil-local required data
+     * \param scvf The sub-control volume face for which the flux term is to be computed
+     * \note This must be overloaded by the implementation
+     */
+    template<class Problem>
+    static FluxTerm flux(const Problem& problem,
+                         const LocalContext& context,
+                         const SubControlVolumeFace& scvf)
+    { DUNE_THROW(Dune::NotImplemented, "This model does not implement a flux method!"); }
+
+    /*!
+     * \brief Compute the source term of the equations for the given sub-control volume
+     * \param problem The problem to be solved (could store additionally required quantities)
+     * \param context The element-stencil-local required data
+     * \param scv The sub-control volume for which the source term is to be computed
+     * \note This is a default implementation forwarding to interfaces in the problem
+     */
+     template<class Problem>
+     static SourceTerm source(const Problem& problem,
+                              const LocalContext& context,
+                              const SubControlVolume& scv)
+    {
+        SourceTerm source(0.0);
+
+        // TODO: The problem-interfaces should be adapted to receive context?
+        const auto& fvGeometry = context.elementGridGeometry();
+        const auto& elemVolVars = context.elementVariables().elemVolVars();
+        const auto& element = fvGeometry.element();
+
+        // add contributions from volume flux sources
+        source += problem.source(element, fvGeometry, elemVolVars, scv);
+
+        // add contribution from possible point sources
+        source += problem.scvPointSources(element, fvGeometry, elemVolVars, scv);
+
+        // multiply with scv volume
+        source *= Extrusion::volume(scv)*elemVolVars[scv].extrusionFactor();
+
+        return source;
+    }
+};
+
+} // end namespace Dumux::Experimental
+
+#endif