Examples

Bornholm’s groundwater bodies characterization

Grid and topography of the domain visualized in Paraview

In this example, we will simulate the arrival of particle in a series of groundwater bodies located in the island of Bornholm, Denmark. All input files are located in the folder examples\Bornholm_groundwater_bodies

Here we detail the provided parameter file:

Input description

General Setup

Here, we specify in which folder outputs (and log file) will be printed, as well as the base name of those outputs. Remember to set the absolute path of your output folder.

..\Bornholm_outputs                                       !... path_outputs
Bornholm                                                  !... basename_outputs

Species and Phases

Our problem involves a single aqueous chemical species that we will call “A”. No mineral species are considered in this simulation.

1  0                                                      !... nspe_aq, nspe_min

A                                                         !... name_aq

Simulation Time and Transport modes

The simulation runs for a total of 1000 time units using forward water transport. It is a steady|state simulation.

1000.0    FW                                              !... t_sim, transport_mode

F                                                         !... transient_flag

Spatial discretization and Boundaries

The model domain is defined with a specific origin and the grid consists of 330 cells in the x-direction, 360 cells in the y-direction and 7 layers. Horizontal spacing is uniform (100 meters), while vertical spacing varies and is read from an external file (DFS3 format). Topography and inactive cells are also specified in a DFS2 and DFS3 file, respectively. All borders of the domain are “open”, i.e., particles will be “killed” if they leave the domain. The grid, topgether will the domain topography and active/inactive cells will be printed in a vtu file for visualization in, e.g., Paraview.

861050.0   6109050.0                                      !... x_origin2, y_origin2

330   360   7                                             !... nx2, ny2, nz2

not_used                       100.0   1   0              !... dx array

not_used                       100.0   1   0              !... dy array

dz_opl71.dfs3                  1.0     1   3   F          !... dz array

topography_opl71.dfs2          1.0     1   3              !... topography elevation array

InactCell_opl71.dfs3           1.0     1   3   T          !... inactive

0 0 0 0 0 0                                               !... ibound

T                                                         !... print grid to vtu file (Paraview)

Time Discretization

Time stepping is controlled using a constant Courant number method. Additional parameters include Peclet number and coefficients for kinetic, decay, and MRMT processes. Those will not be used, but need to be specified. The slowest 1% particles will be disregarded in the time step calculation by setting the relaxation factor to 0.99.

constant_cu                                               !... dt_method

0.5  0.2  0.2  0.1  0.1  0.1                              !... dt, cu, pe, da_kinetic, da_decay, da_mrmt

0.99                                                      !... time_step relaxation

Advection

Advection is enabled and handled using an Eulerian approach. Velocity fields in all three directions and porosity are read from external files (DFS3 files). Flows are provided in x and y directions and need then be converted to fluxes within the code, while fluxes are directly provided in the z-direction.

T                                                         !... advection_action

Eulerian                                                  !... advection_method

Qx_opl71.dfs3                  1.0   1   3   F   T        !... qx array

Qy_opl71.dfs3                  1.0   1   3   F   T        !... qy array

qz_opl71.dfs3                  1.0   1   3   F   F        !... qz array

porosity_opl71.DFS3            1.0   1   3   F            !... porosity array

Heads

Hydraulic heads are included in the simulation and read from a DFS3 file. A minimum head threshold is set to 5 cm to identify dry cells.

T                                                         !... heads_action

heads_opl71.dfs3               1.0   1   3   F            !... heads array

0.05                                                      !... dry_cell_threshold

Sinks

Four types of sinks are defined: river, drain, unsaturated zone, and well. Each is associated with a specific input file (all read from a DFS file). Arrival into each sink will be recorded in a breakthrough curve.

T                                                         !... sink_action

4                                                         !... sink_number

river  Qriver_opl71.dfs3       1.0   1   3   F   T        !... name, qsink array

drain  Qdrain_opl71.dfs3       1.0   1   3   F   T        !... name, qsink array

uz     Qrech_opl71.dfs2        1.0   1   3   F   T        !... name, qsink array

well   Qwell_opl71.dfs3        1.0   1   3   F   T        !... name, qsink array

Dispersion / Diffusion

Dispersion and diffusion processes are not considered in this test case.

F                                                         !... dispersion_action

Mass transfer

Mass transfer between mobile and immobile zones is disabled.

F                                                         !... mrmt_action

Retardation

Chemical retardation effects are not included in this simulation.

F                                                         !... retardation_action

Linear reaction

Linear decay reactions are not modeled in this test case.

F                                                         !... decay_action

Bimolecular reaction

No bimolecular reactions are considered.

F                                                         !... kinetic_action

Control surface

Six regional lenses are defined for breakthrough curve analysis. The extent and boundaries (top and bottom elevations) are specified using DFS2 files. For each lense, a DFS2 file specifying registration codes cell by cell is provided. Each registration code correspond to a specific groundwater body. Time and location of every particle entery and exit into/from each registration code (i.e., groundwater body) will be recorded.

0   F                                                     !... nwell

0   F                                                     !... nplane

6                                                         !... nreglens

330   360                                                 !... nx2, ny2

not_used                         100.0   1   0            !... dx array

not_used                         100.0   1   0            !... dy array

F   T

reglenses\bottom_layer1.dfs2     1.0   1   3   F

reglenses\top_layer1.dfs2        1.0   1   3   F

reglenses\regcodes_layer1.dfs2   1.0   1   3

F   T

reglenses\bottom_layer2.dfs2     1.0   1   3   F

reglenses\top_layer2.dfs2        1.0   1   3   F

reglenses\regcodes_layer2.dfs2   1.0   1   3

F   T

reglenses\bottom_layer3.dfs2     1.0   1   3   F

reglenses\top_layer3.dfs2        1.0   1   3   F

reglenses\regcodes_layer3.dfs2   1.0   1   3

F   T

reglenses\bottom_layer4.dfs2     1.0   1   3   F

reglenses\top_layer4.dfs2        1.0   1   3   F

reglenses\regcodes_layer4.dfs2   1.0   1   3

F   T

reglenses\bottom_layer5.dfs2     1.0   1   3   F

reglenses\top_layer5.dfs2        1.0   1   3   F

reglenses\regcodes_layer5.dfs2   1.0   1   3

F   T

reglenses\bottom_layer6.dfs2     1.0   1   3   F

reglenses\top_layer6.dfs2        1.0   1   3   F

reglenses\regcodes_layer6.dfs2   1.0   1   3

Injection

Initial location of particles

One injection event is defined using a DIRAC pulse in a specific layer. The horizontal extent is read from a DFS2 file. All particles are injected at time 0.

1                                                         !... ninj

layer  random   DIRAC  T                                  !... name_inj, type_inj

1   0     1                                               !... pmass,zone,specie

6   10   0.9   T                                          !... lay_inj2,np_cell,lay_loc,horizontal_extent

injection_extent.dfs2      1.0   1   3                    !... horizontal_extent

0.0                                                       !... tinj

Recirculation

Recirculation is not enabled in this test case.

F                                                         !... recirculation_action

Outputs

Finally, we want to print 100 plume snapshots, from t=0 to t=1000 years. We will also print the cumulative breakthrough curves, as well of the full plume history.

0                                                         !... ixmom

1   0                                                     !... iwcshot, output_format

1000   100   1

0                                                         !... itmom

0   100   plugin   -10.   0.0   250.0    0                !... iwbtc, ngrid, Kernel, bw, tmin, tmax, output_format

1   1   0                                                 !... iwcbtc, inc, output_format

1   0   0                                                 !... iwhistory, print_out, output_format

0   1   1   0                                             !... iwpath, pathfreq, pathpart, output_format

Output Analysis

Running RW3D using this parameter file will produce a series of csv files corresponding to breakthrough curves of particles in and out each groundwater body, and each sink:

Breakthrough curves for all particles entering groundwater bodies.

A series of particle snapshots (location and key properties at a given time) will also be printed into a corresponding series of csv files. Those can be directly imported into Paraview for 3D visualization.

Plume snapshots.

Reactive transport

… coming soon