Exercise Basics (DuMuX course)

Problem set-up

N_2 is injected in an aquifer previously saturated with water with an injection rate of 0.0001 kg/(s*m^2). The aquifer is situated 2700 m below sea level and the domain size is 60 m x 40 m. It consists of two layers, a moderately permeable one (\Omega_1) and a lower permeable one (\Omega_2).

Preparing the exercise

• Navigate to the directory dumux-course/exercises/exercise-basic

This exercise deals with two problems: a two-phase immiscible problem (2p) and a two-phase compositional problem (2p2c). They both set up the same scenario with the difference that the 2p2c assumes a miscible fluid state for the two fluids (water and gaseous N_2) and the 2p model assumes an immiscible fluid state.

Task 1: Getting familiar with the code

Locate all the files you will need for this exercise

• The main file for the 2p problem : 2pmain.cc
• The main file for the 2p2c problem : 2p2cmain.cc
• The problem file for the 2p problem: injection2pproblem.hh
• The problem file for the 2p2c problem: injection2p2cproblem.hh
• The properties file for the __2p__problem: properties2p.hh
• The properties file for the __2p2c__problem: properties2p2c.hh
• The shared spatial parameters file: injection2pspatialparams.hh
• The shared input file: params.input

Task 2: Compiling and running an executable

• Change to the build-directory

cd ../../build-cmake/exercises/exercise-basic

• Compile both executables exercise_basic_2p and exercise_basic_2p2c

make exercise_basic_2p exercise_basic_2p2c

• Execute the two problems and inspect the result

./exercise_basic_2p params.input
./exercise_basic_2p2c params.input

• you can look at the results with paraview

paraview injection-2p2c.pvd

Task 3: Setting up a new executable (for a non-isothermal simulation)

• Copy the main file 2pmain.cc and rename it to 2pnimain.cc
• In 2pnimain.cc, include the header properties2pni.hh instead of properties2p.hh.
• In 2pnimain.cc, change Injection2pCC to Injection2pNICC in the line using TypeTag = Properties::TTag::Injection2pNICC;
• Add a new executable in CMakeLists.txt by adding the lines

# the two-phase non-isothermal simulation program
dune_add_test(NAME exercise_basic_2pni
              SOURCES 2pnimain.cc)

• Test that everything compiles without error

make # should rerun cmake
make exercise_basic_2pni # builds new executable

Task 4: Setting up a non-isothermal 2pni test problem

• Open the files injection2pniproblem.hh and properties2pni.hh. These are a copies of the injection2pproblem.hh properties2pni.hh files, with some useful comments on how to implement a non-isothermal model. Look for comments containing

// TODO: dumux-course-task 4

• The following set-up should be realized:

  Boundary conditions: Dirichlet conditions at the left boundary. For the primary variable 'temperature' use a varying temperature of
  \displaystyle T(y) = 283~\text{K} + 0.03~\frac{\text{K}}{\text{m}} \cdot \left( d_\text{aquifer} - y \right) ,
  with the aquifer depth \displaystyle d_\text{aquifer}=2700~\text{m}. Assign Neumann no-flow for the energy balance to the rest of the boundaries.

  Initial conditions: The same temperature gradient as in the boundary conditions with an exception in the subdomain (20 < x < 30, 5 < y < 35), where you assign a constant initial temperature of 380 K.

The non-isothermal model requires additional parameters like the thermal conductivity of the solid component. They are already implemented and set in params.input, you just need to uncomment them.