Generating and Launching Cases

Scripts used in the different studies are separated in two main folders, namely pre_processing and post_processing.

wall_wetting_zahedi_2009_comparison/scripts/
├── post_processing
│   ├── compare_figure_2.py
│   ├── compare_figure_3.py
│   ├── compare_figure_4.py
│   ├── compare_figure_5a.py
│   ├── compare_figure_5b.py
│   ├── compare_figure_6.py
│   └── post_process_cases.sh
├── pre_processing
│   ├── case_parameters.csv
│   ├── generate_cases.sh
│   ├── launch_cases.sh
│   └── zahedi_wall_wetting.tpl
└── README.md

1. The pre_processing folder contains scripts and files necessary to create and launch cases:
   • Bash script to generate cases: generate_cases.sh
   • Bash script to launch cases: launch_cases.sh
   • CSV file containing a list of cases and their parameters: case_parameters.csv
   • Template JSON parameter file: zahedi_wall_wetting.tpl
2. The post_processing folder contains scripts and files necessary to post-process the simulation results and generate comparison figures.
   • Bash script to post-process and generate all comparison figures: post_process_cases.sh
   • Folder with results from Zahedi et al. [^1]\: zahedi_results_csv_files/. The folder contains results extracted from the figures 2-6 of Zahedi et al. [^1]. The data is stored in CSV format in subfolders for each figure.
   • Post-processing python scripts that generate comparison figures:
     • compare_figure_2.py: Generates the comparison figure of the final time-step interface contours for different $\eta_\text{n}$ values.
     • compare_figure_3.py: Generates the comparison figure with the time evolution of the contact angle for different $\eta_\text{n}$ values.
     • compare_figure_4.py: Generates the comparison figure with the time evolution of the contact angle for different $\varepsilon_\text{tau}$ values.
     • compare_figure_5a.py: Generates the comparison figure of the final time-step interface contours for different $\varepsilon_\text{tau}$ values.
     • compare_figure_5b.py: Generates a close up of figure 5a near the contact point region.
     • compare_figure_6.py: Generates the comparison figure of the contact angle ratio $(\frac{\alpha}{\alpha_\text{s}})$ as a function of the diffusion coefficient ratio $(\frac{\varepsilon_\text{t}}{\varepsilon_\text{n}})$.

Generating the cases

In the pre_processing/ folder, cases are generated in using the generate_cases.sh bash script with the CSV case parameter file (case_parameters.csv) and the template parameter file (zahedi_wall_wetting.tpl).

The CSV case parameter file takes the following form:

case_name,static_contact_angle,epsilon_n_factor,epsilon_t_factor,gamma_factor,end_time
zahedi_wall_wetting_000,45,8,6,1,0.05
zahedi_wall_wetting_001,45,8,6,2.5,0.05
zahedi_wall_wetting_002,45,8,6,5,0.05
...

Note that the case_name contains the padded case number, i.e. "zahedi_wall_wetting_000" is associated with case #0 and "zahedi_wall_wetting_001" with case #1, and so on.

Cases 0 to 3 correspond to the first study, and cases 4 to 20 correspond to the second study.

One can generate the different cases JSON files by simply running the following command:

./generate_cases.sh

by default, this will generate JSON files in a folder wall_wetting_zahedi_2009_comparison/parameter_files/ for all cases ranging from #0 to #20.

You can specify a different range of cases using the -c argument. For example, running

./generate_cases.sh -c "0-3, 20"

will generate JSON files for cases number 0, 1, 2, 3, and 20. For more information on the different arguments that can be passed on, run:

./generate_cases.sh --help

Running the cases

Calling the launch_cases.sh script in the pre_processing/ folder, as shown below, runs by default simulations for cases 0 to 20 on 20 processes.

./launch_cases.sh

Similar to generate_cases.sh, one can specify which cases to run using the -c argument. The number of processes can also be changed using the -np argument. For more information on the other arguments, use -h or --help.

When launch_cases.sh is called, it:

• runs the specified cases;
• logs the console (terminal) outputs in the wall_wetting_zahedi_2009_comparison/meltpooldg_results/logs/ folder;
• stores simulation outputs such as VTU files and contact angle evolution files (wall_wetting.txt) in subfolders of wall_wetting_zahedi_2009_comparison/meltpooldg_results/ for each case, and;
• creates a summary file named with following syntax contact_angles_summary_${timestamp}.csv (e.g. contact_angles_summary_20250530_144304.csv); the file contains among other things the computed_contact_angle evaluated at $\tau_\text{end}$ of the simulations ran with the script. This file also can be found in the wall_wetting_zahedi_2009_comparison/meltpooldg_results/ folder.

Here's what the tree of the results folder should look like:

wall_wetting_zahedi_2009_comparison/meltpooldg_results
├── comparison_figures
│   ├── zahedi_comparison_figure2_normal_vector_closeup.png
│   ├── zahedi_comparison_figure2.png
│   ├── zahedi_comparison_figure3.png
│   ├── ...
│   └── zahedi_comparison_figure6.png
├── contact_angles_summary_${time_stamp}.csv
├── logs
│   ├── zahedi_wall_wetting_000.txt
│   ├── zahedi_wall_wetting_001.txt
│   ├── ...
│   └── zahedi_wall_wetting_020.txt
├── zahedi_wall_wetting_000
│   ├── wall_wetting_0000.vtu
│   ├── wall_wetting_0001.vtu
│   ├── ...
│   ├── wall_wetting.pvd
│   ├── wall_wetting.txt
│   └── zahedi_wall_wetting_000.json
├── zahedi_wall_wetting_001
│   ├── ...
├── ...
└── zahedi_wall_wetting_020
    └── ...

Post-processing Simulation Results

From the post_processing folder, the post_process_cases.sh script can be run to generate all figures automatically using:

./post_process_cases.sh -r <path_to_file_with_simulation_results_summary>

Calling this script also by default generates a comparison_figures/ folder in the meltpooldg_results/ directory where all figures will be saved. To change this, one may pass a different argument with the -ff or --figures_folder flags. For more information on the other arguments, use -h or --help.

Reference

[^1]: S. Zahedi, K. Gustavsson, and G. Kreiss, “A conservative level set method for contact line dynamics,” J. Comput. Phys., vol. 228, no. 17, pp. 6361–6375, Sep. 2009, doi: 10.1016/j.jcp.2009.05.043.