[material] add new 1p interfacial area law instead of hard coding that in localresidual

dumux/material/fluidmatrixinteractions/1pia/CMakeLists.txt

+install(FILES
+fluidsolidinterfacialareashiwang.hh
+DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/dumux/material/fluidmatrixinteractions/1pia)

dumux/material/fluidmatrixinteractions/1pia/fluidsolidinterfacialareashiwang.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 2 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 Fluidmatrixinteractions
+ * \brief Description of a interfacial area between solid and fluid phase
+ */
+#ifndef FLUIDSOLID_INTERFACIALAREA_SHI_WANG_HH
+#define FLUIDSOLID_INTERFACIALAREA_SHI_WANG_HH
+
+#include <algorithm>
+
+
+namespace Dumux
+{
+/*!
+ * \ingroup Fluidmatrixinteractions
+ * \brief Relation for a simple effective thermal conductivity
+ */
+template<class Scalar>
+class FluidSolidInterfacialAreaShiWang
+{
+public:
+    /*!
+     * \brief Relation for the interfacial area between a fluid and a solid phase
+     * after Shi & Wang, Transport in porous media (2011)
+     *
+     * \return interfacial area
+     */
+    static Scalar fluidSolidInterfacialArea(const Scalar porosity,
+                                            const Scalar characteristicLength)
+    { return 6*(1-porosity)/characteristicLength; }
+};
+}
+#endif

dumux/material/fluidmatrixinteractions/CMakeLists.txt

 add_subdirectory(1p)
+add_subdirectory(1pia)
 add_subdirectory(2p)
 add_subdirectory(2pia)
 add_subdirectory(3p)