 <OpenGeoSysProject>

   <mesh>Twophase_Lia_quad.vtu</mesh>

   <geometry>Twophase_Lia.gml</geometry>

   <processes>

     <process>

       <name>GW23</name>

       <type>TWOPHASE_FLOW_PP</type>

       <integration_order>2</integration_order>

       <jacobian_assembler>

         <type>CentralDifferences</type>

         <component_magnitudes>1e5 1e+4</component_magnitudes>

         <relative_epsilons>1e-7 1e-7</relative_epsilons>

       </jacobian_assembler>

       <process_variables>

         <gas_pressure>gas_pressure</gas_pressure>

         <capillary_pressure>capillary_pressure</capillary_pressure>

       </process_variables>

       <secondary_variables>

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

       </secondary_variables>

       <specific_body_force>0 -9.81</specific_body_force>

       <mass_lumping>true</mass_lumping>

       <temperature>temp</temperature>

     </process>

   </processes>

   <media>

     <medium id="0">

       <phases>

         <phase>

           <type>AqueousLiquid</type>

           <properties>

             <property>

               <name>density</name>

               <type>Constant</type>

               <value>1.0e3</value>

             </property>

             <property>

               <name>viscosity</name>

               <type>Constant</type>

               <value>1e-3</value>

             </property>

           </properties>

         </phase>

         <phase>

           <type>Gas</type>

           <properties>

             <property>

               <name>density</name>

               <type>IdealGasLaw</type>

             </property>

             <property>

               <name>viscosity</name>

               <type>Constant</type>

               <value>1.8e-5</value>

             </property>

             <property>

               <name>molar_mass</name>

               <type>Constant</type>

               <value>0.02896</value>

             </property>

           </properties>

         </phase>

       </phases>

       <properties>

         <property>

           <name>permeability</name>

           <type>Constant</type>

           <value>4.5e-13</value>

         </property>

         <property>

           <name>saturation</name>

           <type>SaturationLiakopoulos</type>

         </property>

         <property>

           <name>relative_permeability</name>

           <type>RelPermLiakopoulos</type>

         </property>

         <property>

           <name>relative_permeability_nonwetting_phase</name>

           <type>RelPermBrooksCoreyNonwettingPhase</type>

           <residual_liquid_saturation>0.2</residual_liquid_saturation>

           <residual_gas_saturation>0.0</residual_gas_saturation>

           <min_relative_permeability>1.0e-4</min_relative_permeability>

           <lambda>3.0</lambda>

         </property>

         <property>

           <name>porosity</name>

           <type>Constant</type>

           <value>0.2975</value>

         </property>

       </properties>

     </medium>

   </media>

   <parameters>

     <parameter>

       <name>pc_Dirichlet_bottom</name>

       <type>Constant</type>

       <value>100.0</value>

     </parameter>

     <parameter>

       <name>pg_Dirichlet_bottom</name>

       <type>Constant</type>

       <value>101325.0</value>

     </parameter>

     <parameter>

       <name>pg_Dirichlet_top</name>

       <type>Constant</type>

       <value>101325.0</value>

     </parameter>

     <parameter>

       <name>pc_0</name>

       <type>Constant</type>

       <values>100.0</values>

     </parameter>

     <parameter>

       <name>pg_0</name>

       <type>Constant</type>

       <value>101325.0</value>

     </parameter>

     <parameter>

       <name>temp</name>

       <type>Constant</type>

       <value>293.15</value>

     </parameter>

     <parameter>

       <name>constant_porosity_parameter</name>

       <type>Constant</type>

       <value>2.975000e-001</value>

     </parameter>

     <parameter>

       <name>kappa1</name>

       <type>Constant</type>

       <values>4.500000e-13</values>

     </parameter>

   </parameters>

   <time_loop>

     <processes>

       <process ref="GW23">

         <nonlinear_solver>basic_newton</nonlinear_solver>

         <convergence_criterion>

           <type>DeltaX</type>

           <norm_type>NORM2</norm_type>

           <abstol>1.e-7</abstol>

         </convergence_criterion>

         <time_discretization>

           <type>BackwardEuler</type>

         </time_discretization>

         <time_stepping>

           <type>FixedTimeStepping</type>

           <t_initial>0</t_initial>

           <t_end>1000.0</t_end>

           <timesteps>

             <pair>

               <repeat>100</repeat>

               <delta_t>0.01</delta_t>

             </pair>

             <pair>

               <repeat>8</repeat>

               <delta_t>1</delta_t>

             </pair>

             <pair>

               <repeat>100</repeat>

               <delta_t>0.01</delta_t>

             </pair>

             <pair>

               <repeat>8</repeat>

               <delta_t>1</delta_t>

             </pair>

           </timesteps>

         </time_stepping>

       </process>

     </processes>

     <output>

       <type>VTK</type>

       <prefix>twophaseflow</prefix>

       <timesteps>

         <pair>

           <repeat>1</repeat>

           <each_steps>1000</each_steps>

         </pair>

       </timesteps>

       <output_iteration_results>false</output_iteration_results>

       <variables>

         <variable>capillary_pressure</variable>

         <variable>gas_pressure</variable>

         <variable>saturation</variable>

       </variables>

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

     </output>

   </time_loop>

   <process_variables>

     <process_variable>

       <name>gas_pressure</name>

       <components>1</components>

       <order>1</order>

       <initial_condition>pg_0</initial_condition>

       <boundary_conditions>

         <boundary_condition>

           <geometrical_set>Twophase_Lia_Geometry</geometrical_set>

           <geometry>TOP</geometry>

           <type>Dirichlet</type>

           <parameter>pg_Dirichlet_top</parameter>

         </boundary_condition>

         <boundary_condition>

           <geometrical_set>Twophase_Lia_Geometry</geometrical_set>

           <geometry>BOTTOM</geometry>

           <type>Dirichlet</type>

           <parameter>pg_Dirichlet_bottom</parameter>

         </boundary_condition>

       </boundary_conditions>

     </process_variable>

     <process_variable>

       <name>capillary_pressure</name>

       <components>1</components>

       <order>1</order>

       <initial_condition>pc_0</initial_condition>

       <boundary_conditions>

         <boundary_condition>

           <geometrical_set>Twophase_Lia_Geometry</geometrical_set>

           <geometry>BOTTOM</geometry>

           <type>Dirichlet</type>

           <parameter>pc_Dirichlet_bottom</parameter>

         </boundary_condition>

       </boundary_conditions>

     </process_variable>

   </process_variables>

   <nonlinear_solvers>

     <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>

       <lis>-i bicgstab -p ilu -tol 1e-18 -maxiter 10000</lis>

       <eigen>

         <solver_type>BiCGSTAB</solver_type>

         <precon_type>ILUT</precon_type>

         <max_iteration_step>10000</max_iteration_step>

         <error_tolerance>1e-18</error_tolerance>

       </eigen>

     </linear_solver>

   </linear_solvers>

 </OpenGeoSysProject>