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A concise guide documenting the steps, issues, and lessons learned when installing OpenFOAM on Termux.
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openfoam-termux-installation-guide.md

Installing OpenFOAM on Termux: Experience, Issues, and Lessons Learned

This document captures the complete experience of installing, testing, and running OpenFOAM on Termux, along with the challenges encountered and the lessons learned along the way.

Table of Contents

Introduction

OpenFOAM is a popular open-source CFD toolbox written in C++. Running it on Termux offers an interesting opportunity to run complex simulations on mobile devices. This guide documents the complete process of searching for, installing, testing, and troubleshooting OpenFOAM on Termux.

Confirmed Working Configuration:

  • OpenFOAM Version: v2406
  • Termux Platform: Android ARM64
  • Architecture: linuxARM64ClangDPInt32Opt

Installation Steps

  1. Search and Install OpenFOAM:

    • Use apt (or its wrapper pkg) to search for OpenFOAM: 
      apt search openfoam
    • Install the package: 
      apt install openfoam

  2. Install Required Dependencies:

    • Install the essential library for proper execution: 
      apt install libandroid-execinfo

  3. Verify Installation Location:

    • Check that OpenFOAM was installed correctly: 
      ls -la /data/data/com.termux/files/usr/opt/
    • You should see the OpenFOAM-v2406 directory.

Environment Setup and Verification

Initial Environment Configuration

  1. Source the OpenFOAM Environment:

    source /data/data/com.termux/files/usr/opt/OpenFOAM-v2406/etc/bashrc

  2. Verify Environment Variables:

    echo "WM_PROJECT_DIR: $WM_PROJECT_DIR"
echo "WM_PROJECT_VERSION: $WM_PROJECT_VERSION"
echo "FOAM_TUTORIALS: $FOAM_TUTORIALS"
echo "FOAM_APPBIN: $FOAM_APPBIN"

    Expected Output:

    WM_PROJECT_DIR: /data/data/com.termux/files/usr/opt/OpenFOAM-v2406
WM_PROJECT_VERSION: v2406
FOAM_TUTORIALS: /data/data/com.termux/files/usr/opt/OpenFOAM-v2406/tutorials
FOAM_APPBIN: /data/data/com.termux/files/usr/opt/OpenFOAM-v2406/platforms/linuxARM64ClangDPInt32Opt/bin

  3. Make Environment Persistent (Optional):

    echo 'source /data/data/com.termux/files/usr/opt/OpenFOAM-v2406/etc/bashrc' >> ~/.bashrc

Verify Core Utilities

# Check utility locations
which blockMesh
which icoFoam
which checkMesh

# Test utility accessibility
icoFoam -help | head -5
blockMesh -help | head -5

Installation Testing

Basic Functionality Test

  1. Navigate to Tutorial Case:

    cd $FOAM_TUTORIALS/incompressible/icoFoam/cavity/cavity
pwd  # Should show the full path to the cavity case

  2. Verify Case Structure:

    ls -la
# Should show directories: 0, constant, system

ls -la system/     # Contains controlDict, blockMeshDict, etc.
ls -la constant/   # Contains transportProperties
ls -la 0/          # Contains initial conditions (U, p)

  3. Clean and Test Mesh Generation:

    # Clean any previous runs
foamCleanTutorials .

# Generate mesh
blockMesh

    Successful Output Should Include:

    Creating block mesh from "system/blockMeshDict"
...
Mesh Information
----------------
  boundingBox: (0 0 0) (0.1 0.1 0.01)
  nPoints: 882
  nCells: 400
  nFaces: 1640
...
End

  4. Verify Mesh Quality:

    checkMesh

  5. Test Solver (Short Run):

    # Run solver for 30 seconds to test functionality
timeout 30s icoFoam

# Check if time directories were created
ls -la | grep "^d.*[0-9]"

Success Criteria

Your OpenFOAM installation is working correctly if:

✅ Environment Setup: All environment variables are properly set
✅ Utilities Available: Core utilities (blockMesh, icoFoam) are accessible
✅ Mesh Generation: blockMesh completes without errors
✅ Mesh Validation: checkMesh reports no critical errors
✅ Solver Execution: icoFoam starts and runs without immediate crashes
✅ Result Generation: Time directories and field files are created

Encountered Issues and Fixes

Missing Library: libandroid-execinfo

  • Issue:
    When running icoFoam, an error was thrown indicating that the library libandroid-execinfo.so was missing.

  • Fix:
    Install the missing library:

    apt install libandroid-execinfo

    Verify the library installation:

    ls /data/data/com.termux/files/usr/lib | grep libandroid-execinfo
ldd $(which icoFoam) | grep -i execinfo

Environment Setup and Sourcing

  • Issue:
    Environment variables are empty or not set, indicating the OpenFOAM environment hasn't been sourced.

  • Symptoms:

    echo $WM_PROJECT_DIR  # Returns empty
echo $WM_PROJECT_VERSION  # Returns empty

  • Fix:
    Source the environment file and verify:

    source /data/data/com.termux/files/usr/opt/OpenFOAM-v2406/etc/bashrc
# Re-check environment variables

Case File Errors: Missing or Invalid controlDict

  • Issue:
    Running blockMesh and icoFoam in the tutorial case resulted in errors related to the controlDict file, either missing or containing syntax errors (unexpected '}' error on line 27).

  • Fix Options:

    1. Check Folder Structure:
      Ensure you're in the correct case directory. The tutorial structure is:

      $FOAM_TUTORIALS/incompressible/icoFoam/cavity/
├── cavity/           # Actual case directory
├── cavityClipped/    # Another case variant
└── cavityGrade/      # Another case variant

      Navigate to the specific case: cd cavity/cavity

    2. Restore or Create controlDict:
      If the system/controlDict is missing, use a minimal example such as:

      FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      controlDict;
}

application     icoFoam;

startFrom       startTime;
startTime       0;
stopAt          endTime;
endTime         0.01;
deltaT          0.001;

writeControl    timeStep;
writeInterval   1;
purgeWrite      0;
writeFormat     ascii;
writePrecision  6;
writeCompression off;
timeFormat      general;
timePrecision   6;
runTimeModifiable true;

    3. Syntax Corrections:
      For syntax errors, inspect the controlDict file and remove extraneous braces or misconfigurations.

Tutorial Directory Navigation

  • Issue:
    Confusion about the correct tutorial directory structure and which directory contains the actual case files.

  • Symptoms:

    ls -la constant/  # No such file or directory
ls -la 0/         # No such file or directory

  • Fix:
    Navigate to the correct subdirectory:

    cd $FOAM_TUTORIALS/incompressible/icoFoam/cavity/cavity
# Note the double "cavity" - first is the tutorial group, second is the specific case

Lessons Learned

  • Environment Sourcing is Critical:
    The OpenFOAM environment must be sourced in every new terminal session. Consider adding the source command to your .bashrc for convenience.

  • Verify File Paths:
    Confirm the correct paths for environment files immediately after installation. Packages on Termux might follow a different directory structure than traditional Linux installations.

  • Install Dependencies Promptly:
    Missing library errors (like that for libandroid-execinfo) can block execution. Always ensure dependencies are met before running simulations.

  • Tutorial Directory Structure:
    OpenFOAM tutorials often have nested directory structures. Always navigate to the actual case directory (the one containing system/, constant/, and 0/ directories).

  • Incremental Testing:
    Test each component separately: environment setup → utilities → mesh generation → solver execution. This approach helps isolate issues quickly.

  • Case Cleaning:
    Always run foamCleanTutorials . before testing to ensure a clean state and avoid conflicts from previous runs.

Performance Considerations

Mobile Device Limitations

  • Memory Usage: CFD simulations are memory-intensive. Monitor RAM usage during longer simulations.
  • Battery Life: Complex simulations can drain battery quickly. Consider connecting to power for extended runs.
  • Thermal Management: Intensive computations may cause device heating. Monitor temperature during long simulations.

Optimization Tips

# Monitor system resources during simulation
free -h              # Check memory usage
df -h               # Check disk space
top -p $(pgrep icoFoam)  # Monitor process performance

Case Size Recommendations

For mobile devices, start with small cases:

  • Mesh size: 400-4000 cells for initial testing
  • Time steps: Short simulation periods (0.01-0.1 seconds)
  • Output frequency: Reduce writeInterval to save storage

Next Steps and Additional Resources

Immediate Next Steps

  1. Run Complete Simulations:

    cd $FOAM_TUTORIALS/incompressible/icoFoam/cavity/cavity
foamCleanTutorials .
blockMesh
icoFoam  # Let it run to completion

  2. Explore Other Tutorials:

    ls $FOAM_TUTORIALS/incompressible/
# Try simpleFoam, pimpleFoam, etc.

  3. Post-Processing:

    • Explore result visualization options available on Termux
    • Learn to extract and analyze simulation data

Performance Benchmarking

  • Test different case sizes to understand device capabilities
  • Compare simulation times with desktop/server installations
  • Document optimal case parameters for mobile execution

Documentation and Community

Advanced Usage

  • Custom Cases: Start building your own simulation cases
  • Parallel Processing: Explore multi-core capabilities if available
  • Scripting: Automate simulation workflows with bash scripts
  • Data Analysis: Use Python or other tools for post-processing results

Note: This guide reflects a successfully tested installation on Termux with OpenFOAM v2406. The core functionality has been verified through mesh generation and solver execution tests.

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