diff --git a/Documentation/ProjectFile/prj/process_variables/process_variable/source_terms/source_term/Volumetric/c_Volumetric.md b/Documentation/ProjectFile/prj/process_variables/process_variable/source_terms/source_term/Volumetric/c_Volumetric.md
new file mode 100644
index 0000000000000000000000000000000000000000..731c3267827f90ec1dc97888000bf3cca46f6bac
--- /dev/null
+++ b/Documentation/ProjectFile/prj/process_variables/process_variable/source_terms/source_term/Volumetric/c_Volumetric.md
@@ -0,0 +1,3 @@
+Declares a source term that is defined on the entire domain.
+
+The user should carefully check which physical quantity that parameter is.
diff --git a/Documentation/ProjectFile/prj/process_variables/process_variable/source_terms/source_term/Volumetric/t_parameter.md b/Documentation/ProjectFile/prj/process_variables/process_variable/source_terms/source_term/Volumetric/t_parameter.md
new file mode 100644
index 0000000000000000000000000000000000000000..c8d721a55533cdfa72ed977a48b43a24e1a18a8d
--- /dev/null
+++ b/Documentation/ProjectFile/prj/process_variables/process_variable/source_terms/source_term/Volumetric/t_parameter.md
@@ -0,0 +1,4 @@
+The name of the parameter that defines the value that should be used for the source
+term. Nodal parameters are not supported.
+
+The user should carefully check which physical quantity that parameter is.
diff --git a/ProcessLib/GroundwaterFlow/Tests.cmake b/ProcessLib/GroundwaterFlow/Tests.cmake
index 77a293d5b08e4b6bee026178ce00641f903d07bc..c0a1c15c3b140fab501cbbf0fb0913c8aa06b15f 100644
--- a/ProcessLib/GroundwaterFlow/Tests.cmake
+++ b/ProcessLib/GroundwaterFlow/Tests.cmake
@@ -682,6 +682,30 @@ AddTest(
VIS square_1e6__nodal_sources_expected_pcs_0_ts_1_t_1.000000.vtu
)
+AddTest(
+ NAME GroundWaterFlowProcess_VolumetricSourceTerm_square_1e2
+ PATH Elliptic/square_1x1_GroundWaterFlow
+ EXECUTABLE ogs
+ EXECUTABLE_ARGS square_1e2_volumetricsourceterm.prj
+ WRAPPER time
+ TESTER vtkdiff
+ REQUIREMENTS NOT (OGS_USE_LIS OR OGS_USE_MPI)
+ DIFF_DATA
+ square_1x1_quad_1e2_volumetricsourceterm_analytical_solution.vtu square_1e2_volumetricsourceterm_pcs_0_ts_1_t_1.000000.vtu analytical_solution pressure 1e-14 1e-16
+)
+
+AddTest(
+ NAME GroundWaterFlowProcess_VolumetricSourceTerm_square_1e3
+ PATH Elliptic/square_1x1_GroundWaterFlow
+ EXECUTABLE ogs
+ EXECUTABLE_ARGS square_1e3_volumetricsourceterm.prj
+ WRAPPER time
+ TESTER vtkdiff
+ REQUIREMENTS NOT (OGS_USE_LIS OR OGS_USE_MPI)
+ DIFF_DATA
+ square_1x1_quad_1e3_volumetricsourceterm_analytical_solution.vtu square_1e3_volumetricsourceterm_pcs_0_ts_1_t_1.000000.vtu analytical_solution pressure 1e-10 1e-11
+)
+
AddTest(
NAME PythonBCGroundWaterFlowProcessLaplaceEqDirichletNeumann
PATH Elliptic/square_1x1_GroundWaterFlow_Python
diff --git a/ProcessLib/Process.cpp b/ProcessLib/Process.cpp
index 8e4ad70fe293efab5e160756b20911ab4b861ecd..152f2a3fba15e1f7014e318eca822955f75f29eb 100644
--- a/ProcessLib/Process.cpp
+++ b/ProcessLib/Process.cpp
@@ -189,7 +189,7 @@ void Process::assemble(const double t, GlobalVector const& x, GlobalMatrix& M,
(_coupled_solutions) != nullptr ? _coupled_solutions->process_id : 0;
_boundary_conditions[pcs_id].applyNaturalBC(t, x, K, b, nullptr);
- _source_term_collections[pcs_id].integrateNodalSourceTerms(t, b);
+ _source_term_collections[pcs_id].integrate(t, b);
}
void Process::assembleWithJacobian(const double t, GlobalVector const& x,
diff --git a/ProcessLib/Process.h b/ProcessLib/Process.h
index b887d36dc2360751d5c0a0e9b9bc297f1be1e2d8..7de13ac539e0e963233b792c17a05de37ee0b7b5 100644
--- a/ProcessLib/Process.h
+++ b/ProcessLib/Process.h
@@ -21,7 +21,6 @@
#include "ProcessLib/Output/IntegrationPointWriter.h"
#include "ProcessLib/Output/SecondaryVariable.h"
#include "ProcessLib/Parameter/Parameter.h"
-#include "ProcessLib/SourceTerms/NodalSourceTerm.h"
#include "ProcessLib/SourceTerms/SourceTermCollection.h"
#include "AbstractJacobianAssembler.h"
diff --git a/ProcessLib/ProcessVariable.cpp b/ProcessLib/ProcessVariable.cpp
index 71c7508872933e17a9f65ff69d922e6c6fcd12de..475bf1e570fee7a26e26c2689a4228ddbaef0c0f 100644
--- a/ProcessLib/ProcessVariable.cpp
+++ b/ProcessLib/ProcessVariable.cpp
@@ -18,7 +18,7 @@
#include "ProcessLib/BoundaryCondition/BoundaryCondition.h"
#include "ProcessLib/BoundaryCondition/CreateBoundaryCondition.h"
#include "ProcessLib/SourceTerms/CreateSourceTerm.h"
-#include "ProcessLib/SourceTerms/NodalSourceTerm.h"
+#include "ProcessLib/SourceTerms/SourceTerm.h"
#include "ProcessLib/Utils/ProcessUtils.h"
namespace
@@ -211,14 +211,14 @@ ProcessVariable::createBoundaryConditions(
return bcs;
}
-std::vector<std::unique_ptr<NodalSourceTerm>>
+std::vector<std::unique_ptr<SourceTerm>>
ProcessVariable::createSourceTerms(
const NumLib::LocalToGlobalIndexMap& dof_table,
const int variable_id,
unsigned const integration_order,
std::vector<std::unique_ptr<ParameterBase>> const& parameters)
{
- std::vector<std::unique_ptr<NodalSourceTerm>> source_terms;
+ std::vector<std::unique_ptr<SourceTerm>> source_terms;
for (auto& config : _source_term_configs)
source_terms.emplace_back(createSourceTerm(
diff --git a/ProcessLib/ProcessVariable.h b/ProcessLib/ProcessVariable.h
index 24101fb58d235baa106d477b0c7a1033baa35350..383e9761c8fab8a3e1ff86d8be6fbc330c8e0be3 100644
--- a/ProcessLib/ProcessVariable.h
+++ b/ProcessLib/ProcessVariable.h
@@ -25,7 +25,7 @@ class LocalToGlobalIndexMap;
namespace ProcessLib
{
-class NodalSourceTerm;
+class SourceTerm;
class BoundaryCondition;
class Process;
} // namespace ProcessLib
@@ -59,7 +59,7 @@ public:
std::vector<std::unique_ptr<ParameterBase>> const& parameters,
Process const& process);
- std::vector<std::unique_ptr<NodalSourceTerm>> createSourceTerms(
+ std::vector<std::unique_ptr<SourceTerm>> createSourceTerms(
const NumLib::LocalToGlobalIndexMap& dof_table, const int variable_id,
unsigned const integration_order,
std::vector<std::unique_ptr<ParameterBase>> const& parameters);
diff --git a/ProcessLib/SourceTerms/CreateNodalSourceTerm.cpp b/ProcessLib/SourceTerms/CreateNodalSourceTerm.cpp
index 74d792253db3068dc20b20dfeb67719af4d07fee..04c2227954dc8594f1ce424b00c8dc5c4d088530 100644
--- a/ProcessLib/SourceTerms/CreateNodalSourceTerm.cpp
+++ b/ProcessLib/SourceTerms/CreateNodalSourceTerm.cpp
@@ -18,7 +18,7 @@
namespace ProcessLib
{
-std::unique_ptr<NodalSourceTerm> createNodalSourceTerm(
+std::unique_ptr<SourceTerm> createNodalSourceTerm(
BaseLib::ConfigTree const& config, MeshLib::Mesh const& st_mesh,
const NumLib::LocalToGlobalIndexMap& dof_table,
std::size_t const bulk_mesh_id, const int variable_id,
diff --git a/ProcessLib/SourceTerms/CreateNodalSourceTerm.h b/ProcessLib/SourceTerms/CreateNodalSourceTerm.h
index 9144d92f10906d3a3f203202e20a0910edcd6972..9f0c97169452ce473e89ff5c00f7e183afc10b63 100644
--- a/ProcessLib/SourceTerms/CreateNodalSourceTerm.h
+++ b/ProcessLib/SourceTerms/CreateNodalSourceTerm.h
@@ -26,13 +26,13 @@ class LocalToGlobalIndexMap;
}
namespace ProcessLib
{
-class NodalSourceTerm;
+class SourceTerm;
struct ParameterBase;
} // namespace ProcessLib
namespace ProcessLib
{
-std::unique_ptr<NodalSourceTerm> createNodalSourceTerm(
+std::unique_ptr<SourceTerm> createNodalSourceTerm(
BaseLib::ConfigTree const& config, MeshLib::Mesh const& st_mesh,
const NumLib::LocalToGlobalIndexMap& dof_table, std::size_t mesh_id,
const int variable_id, const int component_id,
diff --git a/ProcessLib/SourceTerms/CreateSourceTerm.cpp b/ProcessLib/SourceTerms/CreateSourceTerm.cpp
index 32a4a778c52e5c819cee545bb0276905f5b4dd08..4e50e55f62343ea6eed0a69cb418af8ae9893279 100644
--- a/ProcessLib/SourceTerms/CreateSourceTerm.cpp
+++ b/ProcessLib/SourceTerms/CreateSourceTerm.cpp
@@ -10,16 +10,17 @@
#include "CreateSourceTerm.h"
#include "CreateNodalSourceTerm.h"
-#include "NodalSourceTerm.h"
+#include "CreateVolumetricSourceTerm.h"
+#include "SourceTerm.h"
#include "SourceTermConfig.h"
namespace ProcessLib
{
-std::unique_ptr<NodalSourceTerm> createSourceTerm(
+std::unique_ptr<SourceTerm> createSourceTerm(
const SourceTermConfig& config,
const NumLib::LocalToGlobalIndexMap& dof_table, const MeshLib::Mesh& mesh,
- const int variable_id, const unsigned /*integration_order*/,
- const unsigned /*shapefunction_order*/,
+ const int variable_id, const unsigned integration_order,
+ const unsigned shapefunction_order,
std::vector<std::unique_ptr<ProcessLib::ParameterBase>> const& parameters)
{
//! \ogs_file_param{prj__process_variables__process_variable__source_terms__source_term__type}
@@ -32,6 +33,14 @@ std::unique_ptr<NodalSourceTerm> createSourceTerm(
*config.component_id, parameters);
}
+ if (type == "Volumetric")
+ {
+ return ProcessLib::createVolumetricSourceTerm(
+ config.config, config.mesh, dof_table, parameters,
+ integration_order, shapefunction_order, variable_id,
+ *config.component_id);
+ }
+
OGS_FATAL("Unknown source term type: `%s'.", type.c_str());
}
} // namespace ProcessLib
diff --git a/ProcessLib/SourceTerms/CreateSourceTerm.h b/ProcessLib/SourceTerms/CreateSourceTerm.h
index 41c058997448b0cbe4f50fd3fb3c18ffb77e2303..ddec4e111b6e523cdf1dae5488b6b551212fc09c 100644
--- a/ProcessLib/SourceTerms/CreateSourceTerm.h
+++ b/ProcessLib/SourceTerms/CreateSourceTerm.h
@@ -26,13 +26,14 @@ class LocalToGlobalIndexMap;
namespace ProcessLib
{
+class SourceTerm;
class NodalSourceTerm;
struct SourceTermConfig;
} // namespace ProcessLib
namespace ProcessLib
{
-std::unique_ptr<NodalSourceTerm> createSourceTerm(
+std::unique_ptr<SourceTerm> createSourceTerm(
const SourceTermConfig& config,
const NumLib::LocalToGlobalIndexMap& dof_table, const MeshLib::Mesh& mesh,
const int variable_id, const unsigned integration_order,
diff --git a/ProcessLib/SourceTerms/CreateVolumetricSourceTerm.cpp b/ProcessLib/SourceTerms/CreateVolumetricSourceTerm.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..93a1f5d0adf090026a4bc787f4b9edc402e1700d
--- /dev/null
+++ b/ProcessLib/SourceTerms/CreateVolumetricSourceTerm.cpp
@@ -0,0 +1,50 @@
+/**
+ * \copyright
+ * Copyright (c) 2012-2018, OpenGeoSys Community (http://www.opengeosys.org)
+ * Distributed under a Modified BSD License.
+ * See accompanying file LICENSE.txt or
+ * http://www.opengeosys.org/project/license
+ *
+ */
+
+#include "CreateVolumetricSourceTerm.h"
+
+#include "BaseLib/ConfigTree.h"
+#include "BaseLib/FileTools.h"
+#include "MeshLib/Mesh.h"
+#include "NumLib/DOF/LocalToGlobalIndexMap.h"
+#include "ProcessLib/Utils/ProcessUtils.h"
+#include "VolumetricSourceTerm.h"
+
+namespace ProcessLib
+{
+std::unique_ptr<SourceTerm> createVolumetricSourceTerm(
+ BaseLib::ConfigTree const& config,
+ MeshLib::Mesh const& source_term_mesh,
+ NumLib::LocalToGlobalIndexMap const& source_term_dof_table,
+ std::vector<std::unique_ptr<ParameterBase>> const& parameters,
+ unsigned const integration_order, unsigned const shapefunction_order,
+ int const variable_id, int const component_id)
+{
+ //! \ogs_file_param{prj__process_variables__process_variable__source_terms__source_term__type}
+ config.checkConfigParameter("type", "Volumetric");
+
+ DBUG("Constructing VolumetricSourceTerm from config.");
+
+ // source term field name
+ auto const& volumetric_source_term_parameter_name =
+ //! \ogs_file_param{prj__process_variables__process_variable__source_terms__source_term__Volumetric__parameter}
+ config.getConfigParameter<std::string>("parameter");
+ auto& volumetric_source_term = findParameter<double>(
+ volumetric_source_term_parameter_name, parameters, 1);
+
+ DBUG("Using '%s` as volumetric source term parameter.",
+ volumetric_source_term.name.c_str());
+
+ return std::make_unique<VolumetricSourceTerm>(
+ source_term_mesh, source_term_dof_table, integration_order,
+ shapefunction_order, variable_id, component_id,
+ volumetric_source_term);
+}
+
+} // namespace ProcessLib
diff --git a/ProcessLib/SourceTerms/CreateVolumetricSourceTerm.h b/ProcessLib/SourceTerms/CreateVolumetricSourceTerm.h
new file mode 100644
index 0000000000000000000000000000000000000000..2f1fcb62c54f9b02116d790d44a1021d71b7bd9f
--- /dev/null
+++ b/ProcessLib/SourceTerms/CreateVolumetricSourceTerm.h
@@ -0,0 +1,43 @@
+/**
+ * \copyright
+ * Copyright (c) 2012-2018, OpenGeoSys Community (http://www.opengeosys.org)
+ * Distributed under a Modified BSD License.
+ * See accompanying file LICENSE.txt or
+ * http://www.opengeosys.org/project/license
+ *
+ */
+
+#pragma once
+
+#include <memory>
+#include <vector>
+
+namespace BaseLib
+{
+class ConfigTree;
+}
+
+namespace MeshLib
+{
+class Mesh;
+}
+
+namespace NumLib
+{
+class LocalToGlobalIndexMap;
+}
+
+namespace ProcessLib
+{
+struct ParameterBase;
+class SourceTerm;
+
+std::unique_ptr<SourceTerm> createVolumetricSourceTerm(
+ BaseLib::ConfigTree const& config,
+ MeshLib::Mesh const& source_term_mesh,
+ NumLib::LocalToGlobalIndexMap const& source_term_dof_table,
+ std::vector<std::unique_ptr<ParameterBase>> const& parameters,
+ unsigned const integration_order, unsigned const shapefunction_order,
+ int const variable_id, int const component_id);
+
+} // namespace ProcessLib
diff --git a/ProcessLib/SourceTerms/NodalSourceTerm.cpp b/ProcessLib/SourceTerms/NodalSourceTerm.cpp
index e621545dce87902e70b728270c4b489b0a478333..04d8619f2ed413923c7fb21239bf2160de672cad 100644
--- a/ProcessLib/SourceTerms/NodalSourceTerm.cpp
+++ b/ProcessLib/SourceTerms/NodalSourceTerm.cpp
@@ -13,13 +13,14 @@
namespace ProcessLib
{
-NodalSourceTerm::NodalSourceTerm(const NumLib::LocalToGlobalIndexMap& dof_table,
- std::size_t const bulk_mesh_id,
- MeshLib::Mesh const& st_mesh,
- const int variable_id,
- const int component_id,
- Parameter<double> const& parameter)
- : _dof_table(dof_table),
+NodalSourceTerm::NodalSourceTerm(
+ const NumLib::LocalToGlobalIndexMap& source_term_dof_table,
+ std::size_t const bulk_mesh_id,
+ MeshLib::Mesh const& st_mesh,
+ const int variable_id,
+ const int component_id,
+ Parameter<double> const& parameter)
+ : SourceTerm(source_term_dof_table),
_bulk_mesh_id(bulk_mesh_id),
_st_mesh(st_mesh),
_variable_id(variable_id),
@@ -36,8 +37,7 @@ NodalSourceTerm::NodalSourceTerm(const NumLib::LocalToGlobalIndexMap& dof_table,
}
}
-void NodalSourceTerm::integrateNodalSourceTerm(const double t,
- GlobalVector& b) const
+void NodalSourceTerm::integrate(const double t, GlobalVector& b) const
{
DBUG("Assemble NodalSourceTerm.");
@@ -49,8 +49,8 @@ void NodalSourceTerm::integrateNodalSourceTerm(const double t,
auto const node_id = node->getID();
MeshLib::Location const l{_bulk_mesh_id, MeshLib::MeshItemType::Node,
bulk_node_ids_map[node_id]};
- auto const index =
- _dof_table.getGlobalIndex(l, _variable_id, _component_id);
+ auto const index = _source_term_dof_table.getGlobalIndex(
+ l, _variable_id, _component_id);
SpatialPosition pos;
pos.setNodeID(node_id);
diff --git a/ProcessLib/SourceTerms/NodalSourceTerm.h b/ProcessLib/SourceTerms/NodalSourceTerm.h
index 4e51bda3caef087031a8753bd2eb9cbc66ff5142..cc22ee10a8110f9f3db01bc2d60ddc538a965c90 100644
--- a/ProcessLib/SourceTerms/NodalSourceTerm.h
+++ b/ProcessLib/SourceTerms/NodalSourceTerm.h
@@ -9,23 +9,22 @@
#pragma once
-#include "NumLib/DOF/LocalToGlobalIndexMap.h"
-#include "ProcessLib/Parameter/Parameter.h"
+#include "SourceTerm.h"
namespace ProcessLib
{
-class NodalSourceTerm final
+class NodalSourceTerm final : public SourceTerm
{
public:
- NodalSourceTerm(const NumLib::LocalToGlobalIndexMap& dof_table,
- std::size_t const bulk_mesh_id,
- MeshLib::Mesh const& st_mesh, const int variable_id,
- const int component_id, Parameter<double> const& parameter);
+ explicit NodalSourceTerm(
+ const NumLib::LocalToGlobalIndexMap& source_term_dof_table,
+ std::size_t const bulk_mesh_id, MeshLib::Mesh const& st_mesh,
+ const int variable_id, const int component_id,
+ Parameter<double> const& parameter);
- void integrateNodalSourceTerm(const double t, GlobalVector& b) const;
+ void integrate(const double t, GlobalVector& b) const override;
private:
- NumLib::LocalToGlobalIndexMap const& _dof_table;
std::size_t const _bulk_mesh_id;
MeshLib::Mesh const& _st_mesh;
int const _variable_id;
diff --git a/ProcessLib/SourceTerms/SourceTerm.h b/ProcessLib/SourceTerms/SourceTerm.h
new file mode 100644
index 0000000000000000000000000000000000000000..bbbd878a3e9a4e509a8954fc7909393293f20f30
--- /dev/null
+++ b/ProcessLib/SourceTerms/SourceTerm.h
@@ -0,0 +1,34 @@
+/**
+ * \copyright
+ * Copyright (c) 2012-2018, OpenGeoSys Community (http://www.opengeosys.org)
+ * Distributed under a Modified BSD License.
+ * See accompanying file LICENSE.txt or
+ * http://www.opengeosys.org/project/license
+ *
+ */
+
+#pragma once
+
+#include "NumLib/DOF/LocalToGlobalIndexMap.h"
+#include "ProcessLib/Parameter/Parameter.h"
+
+namespace ProcessLib
+{
+class SourceTerm
+{
+public:
+ explicit SourceTerm(
+ const NumLib::LocalToGlobalIndexMap& source_term_dof_table)
+ : _source_term_dof_table(source_term_dof_table)
+ {
+ }
+
+ virtual void integrate(const double t, GlobalVector& b) const = 0;
+
+ virtual ~SourceTerm() = default;
+
+protected:
+ NumLib::LocalToGlobalIndexMap const& _source_term_dof_table;
+};
+
+} // namespace ProcessLib
diff --git a/ProcessLib/SourceTerms/SourceTermCollection.cpp b/ProcessLib/SourceTerms/SourceTermCollection.cpp
index f0dc7ba5f978af2efc56d50845392cbde6509e38..9636eae275a4460474d486082e03485bd099e18b 100644
--- a/ProcessLib/SourceTerms/SourceTermCollection.cpp
+++ b/ProcessLib/SourceTerms/SourceTermCollection.cpp
@@ -29,11 +29,10 @@ void SourceTermCollection::addSourceTermsForProcessVariables(
}
}
-void SourceTermCollection::integrateNodalSourceTerms(const double t,
- GlobalVector& b) const
+void SourceTermCollection::integrate(const double t, GlobalVector& b) const
{
for (auto const& st : _source_terms)
- st->integrateNodalSourceTerm(t, b);
+ st->integrate(t, b);
}
}
diff --git a/ProcessLib/SourceTerms/SourceTermCollection.h b/ProcessLib/SourceTerms/SourceTermCollection.h
index bfa7f5a3478fa6e6d69867f143b05356ccae487c..77f8646c23abb1150f08956522373d991cd17e08 100644
--- a/ProcessLib/SourceTerms/SourceTermCollection.h
+++ b/ProcessLib/SourceTerms/SourceTermCollection.h
@@ -10,7 +10,7 @@
#pragma once
#include "ProcessLib/ProcessVariable.h"
-#include "ProcessLib/SourceTerms/NodalSourceTerm.h"
+#include "ProcessLib/SourceTerms/SourceTerm.h"
namespace ProcessLib
{
@@ -23,7 +23,7 @@ public:
{
}
- void integrateNodalSourceTerms(const double t, GlobalVector& b) const;
+ void integrate(const double t, GlobalVector& b) const;
void addSourceTermsForProcessVariables(
std::vector<std::reference_wrapper<ProcessVariable>> const&
@@ -32,7 +32,7 @@ public:
unsigned const integration_order);
private:
- std::vector<std::unique_ptr<NodalSourceTerm>> _source_terms;
+ std::vector<std::unique_ptr<SourceTerm>> _source_terms;
std::vector<std::unique_ptr<ParameterBase>> const& _parameters;
};
diff --git a/ProcessLib/SourceTerms/VolumetricSourceTerm.cpp b/ProcessLib/SourceTerms/VolumetricSourceTerm.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..166405fa84ce45a1c0ab192e58406847675f7359
--- /dev/null
+++ b/ProcessLib/SourceTerms/VolumetricSourceTerm.cpp
@@ -0,0 +1,61 @@
+/**
+ * \copyright
+ * Copyright (c) 2012-2018, OpenGeoSys Community (http://www.opengeosys.org)
+ * Distributed under a Modified BSD License.
+ * See accompanying file LICENSE.txt or
+ * http://www.opengeosys.org/project/license
+ *
+ */
+
+#include "VolumetricSourceTerm.h"
+
+#include "ProcessLib/Utils/CreateLocalAssemblers.h"
+
+namespace ProcessLib
+{
+VolumetricSourceTerm::VolumetricSourceTerm(
+ MeshLib::Mesh const& source_term_mesh,
+ NumLib::LocalToGlobalIndexMap const& source_term_dof_table,
+ unsigned const integration_order, unsigned const shapefunction_order,
+ int const variable_id, int const component_id,
+ Parameter<double> const& volumetric_source_term)
+ : SourceTerm(source_term_dof_table),
+ _volumetric_source_term(volumetric_source_term)
+{
+ // check basic data consistency
+ if (variable_id >=
+ static_cast<int>(source_term_dof_table.getNumberOfVariables()))
+ {
+ OGS_FATAL(
+ "Variable id too high. Actual value: %d, maximum value: %d.",
+ variable_id,
+ source_term_dof_table.getNumberOfVariables());
+ }
+ if (component_id >=
+ source_term_dof_table.getNumberOfVariableComponents(variable_id))
+ {
+ OGS_FATAL(
+ "Component id too high. Actual value: %d, maximum value: %d.",
+ component_id,
+ source_term_dof_table.getNumberOfVariableComponents(variable_id));
+ }
+
+ ProcessLib::createLocalAssemblers<VolumetricSourceTermLocalAssembler>(
+ source_term_mesh.getDimension(), source_term_mesh.getElements(),
+ source_term_dof_table, shapefunction_order, _local_assemblers,
+ source_term_mesh.isAxiallySymmetric(), integration_order,
+ _volumetric_source_term);
+}
+
+void VolumetricSourceTerm::integrate(const double t,
+ GlobalVector& b) const
+{
+ DBUG("Assemble VolumetricSourceTerm.");
+
+ // Call global assembler for each local assembly item.
+ GlobalExecutor::executeMemberOnDereferenced(
+ &VolumetricSourceTermLocalAssemblerInterface::integrate,
+ _local_assemblers, _source_term_dof_table, t, b);
+}
+
+} // namespace ProcessLib
diff --git a/ProcessLib/SourceTerms/VolumetricSourceTerm.h b/ProcessLib/SourceTerms/VolumetricSourceTerm.h
new file mode 100644
index 0000000000000000000000000000000000000000..9f26f93d227613cccd89fa7f23632c8199050dcc
--- /dev/null
+++ b/ProcessLib/SourceTerms/VolumetricSourceTerm.h
@@ -0,0 +1,38 @@
+/**
+ * \copyright
+ * Copyright (c) 2012-2018, OpenGeoSys Community (http://www.opengeosys.org)
+ * Distributed under a Modified BSD License.
+ * See accompanying file LICENSE.txt or
+ * http://www.opengeosys.org/project/license
+ *
+ */
+
+#pragma once
+
+#include <memory>
+#include <vector>
+
+#include "SourceTerm.h"
+#include "VolumetricSourceTermFEM.h"
+
+namespace ProcessLib
+{
+class VolumetricSourceTerm final : public SourceTerm
+{
+public:
+ VolumetricSourceTerm(
+ MeshLib::Mesh const& source_term_mesh,
+ NumLib::LocalToGlobalIndexMap const& source_term_dof_table,
+ unsigned const integration_order, unsigned const shapefunction_order,
+ int const variable_id, int const component_id,
+ Parameter<double> const& volumetric_source_term);
+
+ void integrate(const double t, GlobalVector& b) const;
+
+private:
+ Parameter<double> const& _volumetric_source_term;
+ std::vector<std::unique_ptr<VolumetricSourceTermLocalAssemblerInterface>>
+ _local_assemblers;
+};
+
+} // namespace ProcessLib
diff --git a/ProcessLib/SourceTerms/VolumetricSourceTermFEM.h b/ProcessLib/SourceTerms/VolumetricSourceTermFEM.h
new file mode 100644
index 0000000000000000000000000000000000000000..0cfa15c672b3bf28bf3797ed7845b3ad76da352e
--- /dev/null
+++ b/ProcessLib/SourceTerms/VolumetricSourceTermFEM.h
@@ -0,0 +1,126 @@
+/**
+ * \copyright
+ * Copyright (c) 2012-2018, OpenGeoSys Community (http://www.opengeosys.org)
+ * Distributed under a Modified BSD License.
+ * See accompanying file LICENSE.txt or
+ * http://www.opengeosys.org/project/license
+ *
+ */
+
+#pragma once
+
+#include <vector>
+
+#include "MathLib/LinAlg/Eigen/EigenMapTools.h"
+#include "NumLib/DOF/DOFTableUtil.h"
+#include "NumLib/Fem/FiniteElement/TemplateIsoparametric.h"
+#include "ProcessLib/LocalAssemblerTraits.h"
+#include "ProcessLib/Parameter/Parameter.h"
+#include "ProcessLib/Utils/InitShapeMatrices.h"
+
+namespace ProcessLib
+{
+template <typename NodalRowVectorType>
+struct IntegrationPointData final
+{
+ IntegrationPointData(NodalRowVectorType const& N_,
+ double const& integration_weight_)
+ : integration_weight_times_N(N_ * integration_weight_)
+ {}
+
+ NodalRowVectorType const integration_weight_times_N;
+
+ EIGEN_MAKE_ALIGNED_OPERATOR_NEW;
+};
+
+
+class VolumetricSourceTermLocalAssemblerInterface
+{
+public:
+ virtual void integrate(
+ std::size_t const id,
+ NumLib::LocalToGlobalIndexMap const& source_term_dof_table,
+ double const t, GlobalVector& b) = 0;
+ virtual ~VolumetricSourceTermLocalAssemblerInterface() = default;
+};
+
+const unsigned NUM_NODAL_DOF = 1;
+
+template <typename ShapeFunction, typename IntegrationMethod,
+ unsigned GlobalDim>
+class VolumetricSourceTermLocalAssembler final
+ : public VolumetricSourceTermLocalAssemblerInterface
+{
+ using ShapeMatricesType = ShapeMatrixPolicyType<ShapeFunction, GlobalDim>;
+
+ using LocalAssemblerTraits = ProcessLib::LocalAssemblerTraits<
+ ShapeMatricesType, ShapeFunction::NPOINTS, NUM_NODAL_DOF, GlobalDim>;
+
+ using NodalVectorType = typename LocalAssemblerTraits::LocalVector;
+ using NodalRowVectorType = typename ShapeMatricesType::NodalRowVectorType;
+
+public:
+ VolumetricSourceTermLocalAssembler(
+ MeshLib::Element const& element,
+ std::size_t const local_matrix_size,
+ bool is_axially_symmetric,
+ unsigned const integration_order,
+ Parameter<double> const& volumetric_source_term)
+ : _volumetric_source_term(volumetric_source_term),
+ _integration_method(integration_order),
+ _local_rhs(local_matrix_size)
+ {
+ unsigned const n_integration_points =
+ _integration_method.getNumberOfPoints();
+
+ auto const shape_matrices =
+ initShapeMatrices<ShapeFunction, ShapeMatricesType,
+ IntegrationMethod, GlobalDim>(
+ element, is_axially_symmetric, _integration_method);
+
+ for (unsigned ip = 0; ip < n_integration_points; ip++)
+ {
+ _ip_data.emplace_back(
+ shape_matrices[ip].N,
+ _integration_method.getWeightedPoint(ip).getWeight() *
+ shape_matrices[ip].integralMeasure *
+ shape_matrices[ip].detJ);
+ }
+ }
+
+ void integrate(std::size_t const id,
+ NumLib::LocalToGlobalIndexMap const& source_term_dof_table,
+ double const t, GlobalVector& b) override
+ {
+ _local_rhs.setZero();
+
+ unsigned const n_integration_points =
+ _integration_method.getNumberOfPoints();
+
+ SpatialPosition pos;
+ pos.setElementID(id);
+
+ for (unsigned ip = 0; ip < n_integration_points; ip++)
+ {
+ pos.setIntegrationPoint(ip);
+ auto const st_val = _volumetric_source_term(t, pos)[0];
+
+ _local_rhs.noalias() +=
+ st_val * _ip_data[ip].integration_weight_times_N;
+ }
+ auto const indices = NumLib::getIndices(id, source_term_dof_table);
+ b.add(indices, _local_rhs);
+ }
+
+private:
+ Parameter<double> const& _volumetric_source_term;
+
+ IntegrationMethod const _integration_method;
+ std::vector<
+ IntegrationPointData<NodalRowVectorType>,
+ Eigen::aligned_allocator<IntegrationPointData<NodalRowVectorType>>>
+ _ip_data;
+ NodalVectorType _local_rhs;
+};
+
+} // namespace ProcessLib
diff --git a/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1e2_volumetricsourceterm.prj b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1e2_volumetricsourceterm.prj
new file mode 100644
index 0000000000000000000000000000000000000000..8a0e5fed3b5875dbbabb80062b37968aa08e0961
--- /dev/null
+++ b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1e2_volumetricsourceterm.prj
@@ -0,0 +1,128 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<OpenGeoSysProject>
+ <meshes>
+ <mesh>square_1x1_quad_1e2.vtu</mesh>
+ <mesh>square_1x1_quad_1e2_geometry_right.vtu</mesh>
+ <mesh>square_1x1_quad_1e2_geometry_left.vtu</mesh>
+ </meshes>
+ <processes>
+ <process>
+ <name>GW23</name>
+ <type>GROUNDWATER_FLOW</type>
+ <integration_order>2</integration_order>
+ <hydraulic_conductivity>K</hydraulic_conductivity>
+ <process_variables>
+ <process_variable>pressure</process_variable>
+ </process_variables>
+ <secondary_variables>
+ <secondary_variable type="static" internal_name="darcy_velocity" output_name="v"/>
+ </secondary_variables>
+ </process>
+ </processes>
+ <time_loop>
+ <processes>
+ <process ref="GW23">
+ <nonlinear_solver>basic_picard</nonlinear_solver>
+ <convergence_criterion>
+ <type>DeltaX</type>
+ <norm_type>NORM2</norm_type>
+ <abstol>1.e-6</abstol>
+ </convergence_criterion>
+ <time_discretization>
+ <type>BackwardEuler</type>
+ </time_discretization>
+ <output>
+ <variables>
+ <variable> pressure </variable>
+ <variable> v </variable>
+ </variables>
+ </output>
+ <time_stepping>
+ <type>SingleStep</type>
+ </time_stepping>
+ </process>
+ </processes>
+ <output>
+ <type>VTK</type>
+ <prefix>square_1e2_volumetricsourceterm</prefix>
+ </output>
+ </time_loop>
+ <nonlinear_solvers>
+ <nonlinear_solver>
+ <name>basic_picard</name>
+ <type>Picard</type>
+ <max_iter>10</max_iter>
+ <linear_solver>general_linear_solver</linear_solver>
+ </nonlinear_solver>
+ </nonlinear_solvers>
+ <linear_solvers>
+ <linear_solver>
+ <name>general_linear_solver</name>
+ <lis>-i cg -p jacobi -tol 1e-16 -maxiter 10000</lis>
+ <eigen>
+ <solver_type>CG</solver_type>
+ <precon_type>DIAGONAL</precon_type>
+ <max_iteration_step>10000</max_iteration_step>
+ <error_tolerance>1e-16</error_tolerance>
+ </eigen>
+ <petsc>
+ <prefix>gw</prefix>
+ <parameters>-gw_ksp_type cg -gw_pc_type bjacobi -gw_ksp_rtol 1e-16 -gw_ksp_max_it 10000</parameters>
+ </petsc>
+ </linear_solver>
+ </linear_solvers>
+ <parameters>
+ <parameter>
+ <name>K</name>
+ <type>Constant</type>
+ <value>1</value>
+ </parameter>
+ <parameter>
+ <name>p0</name>
+ <type>Constant</type>
+ <value>0</value>
+ </parameter>
+ <parameter>
+ <name>p_Dirichlet_left</name>
+ <type>Constant</type>
+ <value>2</value>
+ </parameter>
+ <parameter>
+ <name>p_Dirichlet_right</name>
+ <type>Constant</type>
+ <value>1</value>
+ </parameter>
+ <parameter>
+ <name>volumetric_source_term_parameter</name>
+ <type>Constant</type>
+ <value>1</value>
+ </parameter>
+ </parameters>
+ <process_variables>
+ <process_variable>
+ <name>pressure</name>
+ <components>1</components>
+ <order>1</order>
+ <initial_condition>p0</initial_condition>
+ <boundary_conditions>
+ <boundary_condition>
+ <mesh>square_1x1_quad_1e2_geometry_left</mesh>
+ <type>Dirichlet</type>
+ <parameter>p_Dirichlet_left</parameter>
+ </boundary_condition>
+ <boundary_condition>
+ <mesh>square_1x1_quad_1e2_geometry_right</mesh>
+ <type>Dirichlet</type>
+ <parameter>p_Dirichlet_right</parameter>
+ </boundary_condition>
+ </boundary_conditions>
+ <source_terms>
+ <source_term>
+ <mesh>square_1x1_quad_1e2</mesh>
+ <type>Volumetric</type>
+ <parameter>volumetric_source_term_parameter</parameter>
+ </source_term>
+ </source_terms>
+ </process_variable>
+ </process_variables>
+</OpenGeoSysProject>
diff --git a/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1e3_volumetricsourceterm.prj b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1e3_volumetricsourceterm.prj
new file mode 100644
index 0000000000000000000000000000000000000000..23892db304c4d425f47e5de5e62d20f9460653ef
--- /dev/null
+++ b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1e3_volumetricsourceterm.prj
@@ -0,0 +1,128 @@
+<?xml version="1.0" encoding="ISO-8859-1"?>
+<OpenGeoSysProject>
+ <meshes>
+ <mesh>square_1x1_quad_1e3.vtu</mesh>
+ <mesh>square_1x1_quad_1e3_geometry_right.vtu</mesh>
+ <mesh>square_1x1_quad_1e3_geometry_left.vtu</mesh>
+ </meshes>
+ <processes>
+ <process>
+ <name>GW23</name>
+ <type>GROUNDWATER_FLOW</type>
+ <integration_order>2</integration_order>
+ <hydraulic_conductivity>K</hydraulic_conductivity>
+ <process_variables>
+ <process_variable>pressure</process_variable>
+ </process_variables>
+ <secondary_variables>
+ <secondary_variable type="static" internal_name="darcy_velocity" output_name="v"/>
+ </secondary_variables>
+ </process>
+ </processes>
+ <time_loop>
+ <processes>
+ <process ref="GW23">
+ <nonlinear_solver>basic_picard</nonlinear_solver>
+ <convergence_criterion>
+ <type>DeltaX</type>
+ <norm_type>NORM2</norm_type>
+ <abstol>1.e-6</abstol>
+ </convergence_criterion>
+ <time_discretization>
+ <type>BackwardEuler</type>
+ </time_discretization>
+ <output>
+ <variables>
+ <variable> pressure </variable>
+ <variable> v </variable>
+ </variables>
+ </output>
+ <time_stepping>
+ <type>SingleStep</type>
+ </time_stepping>
+ </process>
+ </processes>
+ <output>
+ <type>VTK</type>
+ <prefix>square_1e3_volumetricsourceterm</prefix>
+ </output>
+ </time_loop>
+ <nonlinear_solvers>
+ <nonlinear_solver>
+ <name>basic_picard</name>
+ <type>Picard</type>
+ <max_iter>10</max_iter>
+ <linear_solver>general_linear_solver</linear_solver>
+ </nonlinear_solver>
+ </nonlinear_solvers>
+ <linear_solvers>
+ <linear_solver>
+ <name>general_linear_solver</name>
+ <lis>-i cg -p jacobi -tol 1e-16 -maxiter 10000</lis>
+ <eigen>
+ <solver_type>CG</solver_type>
+ <precon_type>DIAGONAL</precon_type>
+ <max_iteration_step>10000</max_iteration_step>
+ <error_tolerance>1e-16</error_tolerance>
+ </eigen>
+ <petsc>
+ <prefix>gw</prefix>
+ <parameters>-gw_ksp_type cg -gw_pc_type bjacobi -gw_ksp_rtol 1e-16 -gw_ksp_max_it 10000</parameters>
+ </petsc>
+ </linear_solver>
+ </linear_solvers>
+ <parameters>
+ <parameter>
+ <name>K</name>
+ <type>Constant</type>
+ <value>1</value>
+ </parameter>
+ <parameter>
+ <name>p0</name>
+ <type>Constant</type>
+ <value>0</value>
+ </parameter>
+ <parameter>
+ <name>p_Dirichlet_left</name>
+ <type>Constant</type>
+ <value>2</value>
+ </parameter>
+ <parameter>
+ <name>p_Dirichlet_right</name>
+ <type>Constant</type>
+ <value>1</value>
+ </parameter>
+ <parameter>
+ <name>volumetric_source_term_parameter</name>
+ <type>Constant</type>
+ <value>1</value>
+ </parameter>
+ </parameters>
+ <process_variables>
+ <process_variable>
+ <name>pressure</name>
+ <components>1</components>
+ <order>1</order>
+ <initial_condition>p0</initial_condition>
+ <boundary_conditions>
+ <boundary_condition>
+ <mesh>square_1x1_quad_1e3_geometry_left</mesh>
+ <type>Dirichlet</type>
+ <parameter>p_Dirichlet_left</parameter>
+ </boundary_condition>
+ <boundary_condition>
+ <mesh>square_1x1_quad_1e3_geometry_right</mesh>
+ <type>Dirichlet</type>
+ <parameter>p_Dirichlet_right</parameter>
+ </boundary_condition>
+ </boundary_conditions>
+ <source_terms>
+ <source_term>
+ <mesh>square_1x1_quad_1e3</mesh>
+ <type>Volumetric</type>
+ <parameter>volumetric_source_term_parameter</parameter>
+ </source_term>
+ </source_terms>
+ </process_variable>
+ </process_variables>
+</OpenGeoSysProject>
diff --git a/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e2_geometry_left.vtu b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e2_geometry_left.vtu
new file mode 100644
index 0000000000000000000000000000000000000000..d9b5beb7201036cdca9373ddf1abae9f7f9904fc
--- /dev/null
+++ b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e2_geometry_left.vtu
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:718341d2a0bc33a25423a49642d5cbd08f060d5ad1222ae25b0bab77642bdfe0
+size 2096
diff --git a/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e2_geometry_right.vtu b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e2_geometry_right.vtu
new file mode 100644
index 0000000000000000000000000000000000000000..5adcb1cdd6f43f529b2b4099b408463c9a21b255
--- /dev/null
+++ b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e2_geometry_right.vtu
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:9aa273e7328b89475393856c9bfa0dc47d420220293f4d5cfcb1e91a7d418428
+size 2108
diff --git a/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e2_volumetricsourceterm_analytical_solution.vtu b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e2_volumetricsourceterm_analytical_solution.vtu
new file mode 100644
index 0000000000000000000000000000000000000000..197e591e1416522e9c7647b17666409e7bb5e79c
--- /dev/null
+++ b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e2_volumetricsourceterm_analytical_solution.vtu
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:cf14df363af144fb3e9674e4c96a59e82c480c9a46a7b3f7de93fccbc96604cd
+size 7066
diff --git a/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e3_geometry_left.vtu b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e3_geometry_left.vtu
new file mode 100644
index 0000000000000000000000000000000000000000..4c238eff24fa1a4d843ab1e4826f708f2d6b8126
--- /dev/null
+++ b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e3_geometry_left.vtu
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:80905f821e8267dad85ae81560007ecb77be79f7770e4221dae5e53aa1523277
+size 4006
diff --git a/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e3_geometry_right.vtu b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e3_geometry_right.vtu
new file mode 100644
index 0000000000000000000000000000000000000000..284adf21e4a1760e91b97c922fbf38b4f565a458
--- /dev/null
+++ b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e3_geometry_right.vtu
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:a155a8b533695b0c045ec6c6296f357f892a0aa56cf05a127feabc3ec9fd2261
+size 4020
diff --git a/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e3_volumetricsourceterm_analytical_solution.vtu b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e3_volumetricsourceterm_analytical_solution.vtu
new file mode 100644
index 0000000000000000000000000000000000000000..0c91b2345ab4b415c3804114e7d13df860e26a78
--- /dev/null
+++ b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_1e3_volumetricsourceterm_analytical_solution.vtu
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:28a49024ee8db27388b8f77d5917b22e968436e227efb4afd59c94c7afc25728
+size 40894
diff --git a/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_geometry_right.vtu b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_geometry_right.vtu
new file mode 100644
index 0000000000000000000000000000000000000000..5adcb1cdd6f43f529b2b4099b408463c9a21b255
--- /dev/null
+++ b/Tests/Data/Elliptic/square_1x1_GroundWaterFlow/square_1x1_quad_geometry_right.vtu
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:9aa273e7328b89475393856c9bfa0dc47d420220293f4d5cfcb1e91a7d418428
+size 2108
diff --git a/web/content/docs/benchmarks/elliptic/groundwater-flow-dirichlet-volumetric-source-term.pandoc b/web/content/docs/benchmarks/elliptic/groundwater-flow-dirichlet-volumetric-source-term.pandoc
new file mode 100644
index 0000000000000000000000000000000000000000..50905f96bde94a073e0204333462c4502108eba1
--- /dev/null
+++ b/web/content/docs/benchmarks/elliptic/groundwater-flow-dirichlet-volumetric-source-term.pandoc
@@ -0,0 +1,111 @@
++++
+date = "2018-09-25T08:17:39+01:00"
+title = "Groundwater Flow (Volumetric Source Term)"
+project = "Elliptic/square_1x1_GroundWaterFlow/square_1e2_volumetricsourceterm.prj"
+author = "Tom Fischer"
+weight = 102
+
+aliases = [ "/docs/benchmarks/" ] # First benchmark page
+
+[menu]
+ [menu.benchmarks]
+ parent = "elliptic"
+
++++
+
+{{< data-link >}}
+
+## Equations
+
+We start with Poisson equation:
+$$
+\begin{equation}
+k\; \Delta p = Q \quad \text{in }\Omega
+\end{equation}$$
+w.r.t boundary conditions
+$$
+\eqalign{
+p(x) = g_D(x) &\quad \text{on }\Gamma_D,\cr
+k\;{\partial p(x) \over \partial n} = g_N(x) &\quad \text{on }\Gamma_N,
+}$$
+
+where $p$ could be the pressure, the subscripts $D$ and $N$ denote the Dirichlet- and Neumann-type boundary conditions, $n$ is the normal vector pointing outside of $\Omega$, and $\Gamma = \Gamma_D \cup \Gamma_N$ and $\Gamma_D \cap \Gamma_N = \emptyset$.
+
+## Problem specification and analytical solution
+
+We solve the Poisson equation on a square domain $[0\times 1]^2$ with $k = 1$ w.r.t. the specific boundary conditions:
+$$
+\eqalign{
+p(x,y) = 2 &\quad \text{on } (x=0,y) \subset \Gamma_D,\cr
+p(x,y) = 1 &\quad \text{on } (x=1,y) \subset \Gamma_D,\cr
+k\;{\partial p(x,y) \over \partial n} = 0 &\quad \text{on }\Gamma_N.
+}$$
+and the source term is $Q=1$.
+
+The solution of this problem is
+$$
+p(x,y) = - \frac{1}{2} (x^2 + x) + 2.
+$$
+
+## Input files
+
+The main project file is `square_1e2_volumetricsourceterm.prj`. It describes the
+processes to be solved and the related process variables together with their
+initial and boundary conditions. It also references the bulk mesh and the
+boundary meshes associated with the bulk mesh.
+
+The input mesh `square_1x1_quad_1e2.vtu` is stored in the VTK file format and can be directly visualized in Paraview for example.
+
+## Running simulation
+
+To start the simulation (after successful compilation) run:
+```bash
+$ ogs square_1e2_volumetricsourceterm.prj
+```
+
+It will produce some output and write the computed result into the
+`square_1e2_volumetricsourceterm_pcs_0_ts_1_t_1.000000.vtu`, which can be
+directly visualized and analysed in paraview for example.
+
+The output on the console will be similar to the following on:
+```
+info: ConstantParameter: K
+info: ConstantParameter: p0
+info: ConstantParameter: p_Dirichlet_left
+info: ConstantParameter: p_Dirichlet_right
+info: ConstantParameter: volumetric_source_term_parameter
+info: Initialize processes.
+info: Solve processes.
+info: [time] Output of timestep 0 took 0.000408888 s.
+info: === Time stepping at step #1 and time 1 with step size 1
+info: [time] Assembly took 0.000366926 s.
+info: [time] Applying Dirichlet BCs took 3.76701e-05 s.
+info: ------------------------------------------------------------------
+info: *** Eigen solver computation
+info: -> solve with CG (precon DIAGONAL)
+info: iteration: 9/10000
+info: residual: 7.661918e-17
+
+info: ------------------------------------------------------------------
+info: [time] Linear solver took 0.000194073 s.
+info: [time] Iteration #1 took 0.000657082 s.
+info: [time] Solving process #0 took 0.000686884 s in time step #1
+info: [time] Time step #1 took 0.000750065 s.
+info: [time] Output of timestep 1 took 0.000280857 s.
+info: The whole computation of the time stepping took 1 steps, in which
+ the accepted steps are 1, and the rejected steps are 0.
+
+info: [time] Execution took 0.0493069 s.
+info: OGS terminated on 2018-09-25 08:00:58+020
+```
+
+## Results and evaluation
+
+### Comparison of the analytical solution and the computed solution
+
+{{< img src="../square_1e2_volumetricsourceterm_pcs_0_ts_1_t_1.000000_Pressure_AnalyticalSolution_VolumetricSourceTerm.png" >}}
+There is no visible difference between the computed pressure and the analytical
+solution.
+{{< img src="../square_1e2_volumetricsourceterm_pcs_0_ts_1_t_1.000000_Diff_Pressure_AnalyticalSolution_VolumetricSourceTerm.png" >}}
+The difference between the pressure and the analytical solution is the range of
+machine accuracy.
diff --git a/web/content/docs/benchmarks/elliptic/square_1e2_volumetricsourceterm_pcs_0_ts_1_t_1.000000_Diff_Pressure_AnalyticalSolution_VolumetricSourceTerm.png b/web/content/docs/benchmarks/elliptic/square_1e2_volumetricsourceterm_pcs_0_ts_1_t_1.000000_Diff_Pressure_AnalyticalSolution_VolumetricSourceTerm.png
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+version https://git-lfs.github.com/spec/v1
+oid sha256:3c063b973e6e2aef887077ab627ba273727ccd6d4ae964d27cfc25779972532b
+size 16954
diff --git a/web/content/docs/benchmarks/elliptic/square_1e2_volumetricsourceterm_pcs_0_ts_1_t_1.000000_Pressure_AnalyticalSolution_VolumetricSourceTerm.png b/web/content/docs/benchmarks/elliptic/square_1e2_volumetricsourceterm_pcs_0_ts_1_t_1.000000_Pressure_AnalyticalSolution_VolumetricSourceTerm.png
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