hpc-openfoam

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