Quick Start

This guide walks you through running your first RfbFoam simulation using the provided example cases. Make sure you have completed the Installation steps first.

Running a Case

1. Navigate to an example case:

   cd examples/cases/FTFF_Model/

2. Run the full simulation:

   ./Allrun

   This script handles mesh generation, field initialization, domain decomposition, parallel solving, and reconstruction.

3. Clean up (to reset the case):

   ./Allclean

Available Run Scripts

Each example case provides individual scripts for running specific stages:

Script	Description
Allrun	Full workflow: prepare, solve, and reconstruct
Allclean	Remove all generated files and reset the case
Run_Prepare_Only.sh	Mesh generation and field initialization only
Run_All.sh	Full workflow: mesh generation, decomposition, parallel solve, and reconstruction
Run_U.sh	Solve momentum equations only (-onlyU flag)
Run_Scalar.sh	Solve mass and charge transport only (-onlyScalar flag)

Decoupled Workflow

A common workflow is to solve the flow field first, then run the electrochemistry on the converged velocity field. This is useful for parametric studies where the velocity field remains fixed across different applied potentials:

./Run_Prepare_Only.sh   # Generate mesh and initialize fields
./Run_U.sh              # Solve momentum equations
./Run_Scalar.sh         # Solve species and charge transport

tip

The decoupled approach is the recommended workflow for generating polarization curves, since the velocity field does not change with applied potential. Solve the flow once and reuse the results.

Parallel Execution

Important

The example cases are configured to run in parallel using 16 CPU cores by default. If your system has fewer cores (or you want to use a different number), you must adjust this setting before running the simulations.

Checking and Modifying the Number of Cores

The number of parallel processes is controlled by the numberOfSubdomains parameter in the system/decomposeParDict file:

numberOfSubdomains 16;  // Change this to match your available CPU cores

method          scotch;

To change the number of cores:

1. Open system/decomposeParDict in a text editor
2. Change the numberOfSubdomains value to your desired number of cores
3. Save the file

Examples:

• For a 4-core laptop: numberOfSubdomains 4;
• For an 8-core workstation: numberOfSubdomains 8;
• For a 32-core server: numberOfSubdomains 32;

note

Running with more subdomains than available CPU cores will cause significant performance degradation and may lead to system instability. Always match numberOfSubdomains to the number of physical cores you want to dedicate to the simulation.