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name: hpc-openfoam description: Generate, review, debug, and recover OpenFOAM case files for CFD workflows. Use when working with OpenFOAM dictionaries, case structure, turbulence fields, boundary conditions, decomposition, numerics, or OpenFOAM runtime errors. Also covers RANS/LES turbulence setup, wall functions, y+ targeting, conjugate heat transfer, compressible flows, VOF multiphase, mesh quality, and scheme tuning.

HPC OpenFOAM

Follow a progressive loading workflow.

Start

1. Read references/case-setup.md before creating or editing any OpenFOAM case.
2. Read references/solver-selection.md when selecting a solver family or pressure convention.
3. Read references/boundary-condition-playbook.md for concrete BC syntax (fixedValue, inletOutlet, wall functions, etc.).
4. Read references/turbulence-bc-recipes.md for turbulence model setup, inlet value estimation, and wall function selection with y+ guidance.
5. Read references/numerics-and-schemes-guide.md for fvSchemes and fvSolution tuning with scheme selection tables.
6. Read references/case-recipes.md for complete case configurations (internal flow, external aero, VOF, PIMPLE, buoyant).
7. Read references/function-object-recipes.md for probes, forces, yPlus monitoring.
8. Read references/validation-parallel-and-observability.md for validation, post-processing, and parallel execution.
9. Read references/cluster-execution-playbook.md for scheduler-backed cluster execution.
10. Read references/error-recovery.md for diagnostic commands, decision tree, and fix sequences.

Scenario Recipes

Load the relevant recipe when the task involves:

• references/numerics-and-schemes-guide.md — fvSchemes convection/gradient/time schemes, fvSolution solver settings, relaxation factors, SIMPLE/PISO/PIMPLE algorithm controls, progressive scheme upgrade strategy
• references/heat-transfer-and-compressible-cases.md — thermophysicalProperties (Boussinesq, ideal gas, Sutherland), buoyant solvers, conjugate heat transfer (chtMultiRegionFoam), solid properties, fluid-solid coupling BCs
• references/multiphase-vof-recipes.md — interFoam setup, alpha transport, MULES settings, maxAlphaCo, phase initialization (setFields), VOF boundary conditions
• references/mesh-quality-and-generation-guide.md — checkMesh thresholds and interpretation, blockMesh grading, snappyHexMesh workflow, y+ targeted layer meshing

Work Sequence

1. Classify the case first: steady or transient, incompressible or compressible, single-phase or multiphase, laminar or turbulent.
2. Generate the minimum consistent file set across 0/, constant/, and system/. Do not edit one layer in isolation if it changes the required fields elsewhere.
3. Match solver family and fields:
   • simpleFoam or foamRun -solver incompressibleFluid: steady incompressible; expect U, p, and turbulence fields if RAS.
   • pimpleFoam or foamRun -solver incompressibleFluid with transient/PIMPLE settings: transient incompressible; review timestep control and outer correctors.
   • interFoam or foamRun -solver incompressibleVoF: multiphase; control both maxCo and maxAlphaCo.
   • buoyantSimpleFoam / buoyantPimpleFoam: heat transfer; add T, p_rgh, alphat, thermophysicalProperties, g.
   • chtMultiRegionFoam: conjugate heat transfer; multi-region setup with fluid and solid.
4. Validate mesh and numerics before a long run:
   • run blockMesh or the mesh generator
   • run checkMesh — non-orthogonality > 70° needs correctors, > 85° needs remeshing
   • start with conservative schemes (upwind), upgrade to linearUpwind after stability
5. Keep parallel settings aligned:
   • make numberOfSubdomains match the intended MPI rank count
   • prefer scotch for complex geometries unless the user requests a manual layout
6. Resolve executable compatibility before launch:
   • if simpleFoam/pimpleFoam/interFoam exists, it is valid to run directly
   • otherwise prefer foamRun -solver <moduleName> and verify the module loads

Additional References

Load these on demand:

• references/mesh-and-blockmeshdict-manual.md for mesh generation, vertex ordering, and mesh-quality workflow
• references/turbulence-and-numerics.md for turbulence model matching and decomposition choices
• references/fvsolution-and-residual-control.md for algorithm loops, solver blocks, and case termination logic
• references/field-and-dictionary-matrix.md for solver-to-field and file-to-parameter matrices

Guardrails

• Do not invent dictionary keys, patch types, or solver names.
• Do not use turbulence fields that do not match the chosen model family.
• Do not keep aggressive second-order convection schemes during first-pass stabilization on a fragile case.
• Do not treat checkMesh warnings as optional if the log is already diverging.
• Do not use p when the solver expects p_rgh (buoyant/VOF), or vice versa.
• Do not use ISMEAR=-5 equivalent (tetrahedron) — this is a VASP concept, not OpenFOAM.
• Do not use linear (central differencing) for alpha convection in VOF — it is unbounded.
• Do not set relaxation factors to 1.0 in steady-state SIMPLE without SIMPLEC (consistent yes).

Reusable Templates

Use assets/templates/ when a concrete case skeleton is needed:

• simplefoam-minimal/ — minimal steady incompressible case with inline comments explaining scheme and solver choices, plus turbulence upgrade instructions
• interfoam-minimal/ — multiphase checklist placeholder (not a self-contained runnable case)
• openfoam-parallel-slurm.sh — minimal scheduled parallel run scaffold

Outputs

Produce a short case summary that states:

• solver and physics family
• required fields and dictionaries touched
• turbulence model, wall treatment, and estimated inlet turbulence values
• validation commands run or still needed
• stability risks and the next recovery step if the case is failing