gmawFoam

OpenFOAM solvers for wire melting, electromagnetically driven droplet transfer and weld-pool multiphysics in gas metal arc welding (GMAW, MIG/MAG).

Status: private pre-alpha research project. No validated predictive capability is currently claimed.

Current development target

The first executable is gmawTransferFoam, an OpenFOAM-v2606 solver for axisymmetric free-flight transfer from a continuously fed consumable wire. The initial model is deliberately reduced: it resolves electrode and droplet physics while representing the arc through prescribed, normalized loading rather than solving a thermal plasma.

The v0.1 target includes:

• incompressible metal-gas VOF hydrodynamics
• transient thermal transport
• melting, latent heat and liquid fraction
• a translating solid-wire treatment compatible with continuous wire feed
• electric-current conservation in the connected electrode
• prescribed current extraction through the deforming metal-gas interface
• self-induced magnetic field
• Lorentz force and Joule heating
• surface tension and gravity
• prescribed arc heat flux, pressure and, when justified, shear
• droplet growth, necking, detachment and repeated free-flight transfer

The first release does not solve the plasma, weld pool, short-circuit transfer, metal vapour, species chemistry or turbulence.

Parent-solver decision

For OpenFOAM-v2606, the initial parent is the OpenCFD/OpenFOAM.com interFoam solver.

This is a deliberate change from the earlier v2512 architecture spike. The v0.1 problem does not require compressible gas/plasma thermodynamics, while interFoam provides the smaller incompressible VOF/PIMPLE skeleton and already exposes laminar/RAS/LES transport infrastructure for later work.

Other OpenFOAM-v2606 components are implementation references rather than parents:

• icoReactingMultiphaseInterFoam — non-isothermal/phase-change architecture
• compressibleInterFoam and VoFSolidificationMeltingSource — VOF thermal/solidification precedent
• electrostaticFoam — scalar-potential discretization reference
• mhdFoam — electromagnetic-field discretization reference, not the GMAW parent
• magneticFoam — magnetic-field reference

See ADR-0001-parent-solver.md and openfoam-v2606-source-inventory.md.

Planned solver family

Component	Responsibility	Status
gmawTransferFoam	Wire heating, melting, electromagnetic droplet formation and free-flight transfer	v0.1 target
gmawPoolFoam	Droplet impact, weld-pool flow, melting/solidification and pool electromagnetics	Later
gmawPlasmaFoam	Thermal plasma, current transport, magnetic field and arc loading	Later
gmawFoam	Fully coupled wire-arc-droplet-pool system	Long-term target; name reserved

Development method

Every addition follows three separate requirements:

1. Code verification — the intended equation/source is implemented correctly.
2. Solution verification — discretization, iterative and domain errors are quantified.
3. Validation — the model is compared with traceable experimental measurements and uncertainty.

The repository therefore develops in small gated chunks. A visually plausible welding animation is not a milestone criterion.

The complete staged plan is in milestones.md.

Repository structure

gmawFoam/
├── applications/
│   └── solvers/             # solver executables
├── src/                     # reusable project models/libraries
├── tutorials/               # verification and demonstration cases
├── validation/              # experimental comparison cases and analysis
├── reference/               # upstream-source provenance/reference material
├── scripts/
├── AGENTS.md
├── CONTRIBUTING.md
├── CITATION.cff
└── LICENSE

The supplied OpenFOAM tarballs are upstream GPL reference material, not the project implementation. Production code should copy/adapt only the files and fragments actually required, retaining upstream GPL notices and adding project modification notices.

Documentation

• v0.1 scope
• milestones and checkpoints
• governing equations
• verification and validation plan
• welding and physical data requirements
• OpenFOAM-v2606 source inventory
• prior art
• reference-case template
• licensing and attribution
• parent-solver ADR
• current-extraction ADR
• translating-solid-wire ADR
• magnetostatics ADR

Target environment

Primary development target:

OpenFOAM-v2606
OpenCFD/OpenFOAM.com distribution
Linux or WSL2
wmake
OpenMPI for parallel cases

The package-managed OpenFOAM installation is treated as read-only reference material. Project executables are built into $FOAM_USER_APPBIN.

Check the active environment with:

bash scripts/check-openfoam-env.sh

Immediate next implementation chunk

After this documentation/source-review baseline is merged, the next code chunk is intentionally narrow:

1. copy the minimum v2606 interFoam solver files into applications/solvers/gmawTransferFoam;
2. rename the executable and change its build destination to $FOAM_USER_APPBIN;
3. make no physics changes;
4. build with wmake;
5. reproduce an equivalent two-phase VOF smoke case;
6. record the result before adding temperature.

Licence

gmawFoam is licensed under GPL-3.0-or-later.

Code copied or adapted from OpenFOAM or another GPL project must retain the original copyright and licence notice. Project-specific changes add an additional modification/copyright notice; upstream attribution is never removed.

See licensing-and-attribution.md.

Disclaimer

This software is research software under active development. It must not be used to qualify welding procedures, establish production parameters or make safety-critical decisions without independent verification and validation.

OpenFOAM is a registered trade mark of OpenCFD Limited. This project is not approved or endorsed by OpenCFD Limited.