README.md

Exercise #1 (DuMuX course)

## Problem set-up

N_2 is injected in an aquifer previously saturated with water with an injection rate of 0.001 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/tutorial/ex1

Exercise 1 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

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Locate all the files you will need for this exercise

• The main file for the 2p problem : exercise1_2p.cc
• The main file for the 2p2c problem : exercise1_2p2c.cc
• The problem file for the 2p problem: injection2pproblem.hh
• The problem file for the 2p2c problem: injection2p2cproblem.hh
• The shared spatial parameters file: injection2pspatialparams.hh
• The shared input file: exercise1.input

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### Task 2: Compiling and running an executable

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• Change to the build-directory

cd ../../build-cmake/tutorial/ex1

• Compile both executables exercise1_2p and exercise1_2p2c

make exercise1_2p exercise1_2p2c

• Execute the two problems and inspect the result

./exercise1_2p exercise1.input
./exercise1_2p2c exercise1.input

• you can look at the results with paraview

paraview injection-2p2c.pvd

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### Task 3: Changing input parameters

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In the input file exercise1.input you can find the following section

[SpatialParams]
EntryPressureAquitard = 4.5e4
EntryPressureAquifer = 1e4

• Change the values for the aquitard entry pressure in the input file to a lower value and compare the results with the previous solution. You don't need to recompile the executable.

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### Task 4: Runtime parameters

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The injection rate is currently hard-coded in injection2p2cproblem.hh to 1e-4 kg/(s m^2).

 // set the Neumann values for the Nitrogen component balance
 // convert from units kg/(s*m^2) to mole/(s*m^2)
values[Indices::contiNEqIdx] = -1e-4/FluidSystem::molarMass(FluidSystem::nCompIdx);
values[Indices::contiWEqIdx] = 0.0;

We want to be able to set it at runtime. To this end,

• use the following DuMuX macro to read a runtime parameter from the input file

// read the injection rate from the input file at run time
totalAreaSpecificInflow_ = getParam<TYPE>("GROUPNAME.PARAMNAME");

• Replace <TYPE>,<GROUPNAME>,<PARAMNAME> by what is appropriate for your case:
  • <TYPE> is the type of the parameter to read
  • <GROUPNAME> is the group in the input file
  • <PARAMNAME> is the name of the parameter in the input file

Note that due to the way the macro works, the names are specified as plain text within the "quotation marks".<GROUPNAME> and <PARAMNAME> need to be separated by a dot (.). Follow the instructions given as a

// TODO: dumux-course-task