README.md

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 non-isothermal problem (2pni). They both set up the same scenario with the difference that the 2pni model introduces an extra energy equation.

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 problem file for the 2p problem: injection2pproblem.hh
• The problem file for the 2pni problem: injection2pniproblem.hh
• The properties file for the 2p problem: properties2p.hh
• The properties file for the 2pni problem: properties2pni.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 the executable exercise_basic_2p

make exercise_basic_2p

• Execute the problem and inspect the result

./exercise_basic_2p params.input

• you can look at the results with paraview

paraview injection-2p.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
dumux_add_test(NAME exercise_basic_2pni
               SOURCES 2pnimain.cc)

• In the respective build-cmake folder, 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 copies of the injection2pproblem.hh and properties2p.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:

  Initial conditions: 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}. Additionally, add a subdomain (20 < x < 30, 5 < y < 35), where you assign a constant initial temperature of 380 K.

  Boundary conditions: Dirichlet boundary conditions at the left boundary with the same temperature gradient as in the initial conditions. For the Neumann conditions, assign an energy flux at the injection point of N_2 and no-flow conditions for the energy balance to the rest of the boundaries.

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.