 <OpenGeoSysProject>

   <meshes>

     <mesh>mesh1FE.vtu</mesh>

     <mesh>mesh1FE_sub.vtu</mesh>

   </meshes>

   <processes>

     <process>

       <name>HeatConduction</name>

       <type>HEAT_CONDUCTION</type>

       <integration_order>2</integration_order>

       <process_variables>

         <process_variable>temperature</process_variable>

       </process_variables>

       <secondary_variables>

         <secondary_variable internal_name="heat_flux" output_name="heat_flux" />

       </secondary_variables>

       <jacobian_assembler>

         <type>CentralDifferences</type>

       </jacobian_assembler>

     </process>

   </processes>

   <media>

     <medium>

       <phases>

         <phase>

           <type>AqueousLiquid</type>

           <properties>

             <property>

               <name>thermal_conductivity</name>

               <type>Constant</type>

               <value>0</value>

             </property>

             <property>

               <name>specific_heat_capacity</name>

               <type>Constant</type>

               <value>4186</value>

             </property>

             <property>

               <name>density</name>

               <type>Constant</type>

               <value>1000</value>

             </property>

           </properties>

         </phase>

         <phase>

           <type>FrozenLiquid</type>

           <properties>

             <property>

               <name>thermal_conductivity</name>

               <type>Constant</type>

               <value>0</value>

             </property>

             <property>

               <name>specific_heat_capacity</name>

               <type>Constant</type>

               <value>2052</value>

             </property>

             <property>

               <name>density</name>

               <type>Constant</type>

               <value>900</value>

             </property>

           </properties>

         </phase>

         <phase>

           <type>Solid</type>

           <properties>

             <property>

               <name>thermal_conductivity</name>

               <type>Constant</type>

               <value>0</value>

             </property>

             <property>

               <name>specific_heat_capacity</name>

               <type>Constant</type>

               <value>0</value>

             </property>

             <property>

               <name>density</name>

               <type>Constant</type>

               <value>0</value>

             </property>

           </properties>

         </phase>

       </phases>

       <properties>

         <property>

           <name>porosity</name>

           <type>Constant</type>

           <value>1.0</value>

         </property>

         <property>

           <name>volume_fraction</name>

           <type>TemperatureDependentFraction</type>

           <steepness>7</steepness>

           <characteristic_temperature>273.15</characteristic_temperature>

         </property>

         <property>

           <name>density</name>

           <type>VolumeFractionAverage</type>

         </property>

         <property>

           <name>thermal_conductivity</name>

           <type>VolumeFractionAverage</type>

         </property>

         <property>

           <name>specific_heat_capacity</name>

           <type>SpecificHeatCapacityWithLatentHeat</type>

           <specific_latent_heat>700000</specific_latent_heat>

         </property>

       </properties>

     </medium>

   </media>

   <parameters>

     <parameter>

       <name>T0</name>

       <type>Constant</type>

       <value>272.35</value>

     </parameter>

     <parameter>

       <name>HeatSource</name>

       <type>Constant</type>

       <value>1</value>

     </parameter>

   </parameters>

   <process_variables>

     <process_variable>

       <name>temperature</name>

       <components>1</components>

       <order>1</order>

       <initial_condition>T0</initial_condition>

       <boundary_conditions />

       <source_terms>

         <source_term>

           <mesh>mesh1FE_sub</mesh>

           <type>Volumetric</type>

           <parameter>HeatSource</parameter>

         </source_term>

       </source_terms>

     </process_variable>

   </process_variables>

   <time_loop>

     <processes>

       <process ref="HeatConduction">

         <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>

         <time_stepping>

           <type>FixedTimeStepping</type>

           <t_initial>0.0</t_initial>

           <t_end>630e6</t_end>

           <timesteps>

             <pair>

               <repeat>315</repeat>

               <delta_t>2e6</delta_t>

             </pair>

           </timesteps>

         </time_stepping>

       </process>

     </processes>

     <output>

       <type>VTK</type>

       <prefix>Stefan_problem_hom</prefix>

       <timesteps>

         <pair>

           <repeat>10000</repeat>

           <each_steps>1</each_steps>

         </pair>

       </timesteps>

       <variables>

         <variable>temperature</variable>

         <variable>heat_flux</variable>

       </variables>

       <suffix>ts{:timestep}_t_{:time}</suffix>

     </output>

   </time_loop>

   <nonlinear_solvers>

     <nonlinear_solver>

       <name>basic_picard</name>

       <type>Picard</type>

       <max_iter>100</max_iter>

       <linear_solver>general_linear_solver</linear_solver>

     </nonlinear_solver>

     <nonlinear_solver>

       <name>basic_newton</name>

       <type>Newton</type>

       <max_iter>50</max_iter>

       <linear_solver>general_linear_solver</linear_solver>

     </nonlinear_solver>

   </nonlinear_solvers>

   <linear_solvers>

     <linear_solver>

       <name>general_linear_solver</name>

       <eigen>

         <solver_type>SparseLU</solver_type>

         <precon_type>DIAGONAL</precon_type>

       </eigen>

     </linear_solver>

   </linear_solvers>

   <test_definition>

     <vtkdiff>

       <file>Stefan_problem_hom_ts_20_t_40000000.000000.vtu</file>

       <field>temperature</field>

       <absolute_tolerance>2e-11</absolute_tolerance>

       <relative_tolerance>0</relative_tolerance>

     </vtkdiff>

     <vtkdiff>

       <file>Stefan_problem_hom_ts_315_t_630000000.000000.vtu</file>

       <field>temperature</field>

       <absolute_tolerance>5e-10</absolute_tolerance>

       <relative_tolerance>0</relative_tolerance>

     </vtkdiff>

     <vtkdiff>

       <file>Stefan_problem_hom_ts_20_t_40000000.000000.vtu</file>

       <field>heat_flux</field>

       <absolute_tolerance>1e-15</absolute_tolerance>

       <relative_tolerance>0</relative_tolerance>

     </vtkdiff>

     <vtkdiff>

       <file>Stefan_problem_hom_ts_315_t_630000000.000000.vtu</file>

       <field>heat_flux</field>

       <absolute_tolerance>1e-15</absolute_tolerance>

       <relative_tolerance>0</relative_tolerance>

     </vtkdiff>

   </test_definition>

 </OpenGeoSysProject>