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simpleFoam

Steady-state incompressible solver (SIMPLE / SIMPLEC). This is the solver brae ships today, a faithful GPU port of OpenFOAM v2412's simpleFoam, fully device-resident and validated cell-by-cell against OpenFOAM. If your case uses only what is listed here, it should run and match OpenFOAM to under 1%.

<- back to all solvers

At a glance
Algorithm steady incompressible SIMPLE / SIMPLEC
Turbulence (RAS) laminar, k-epsilon, k-omega SST, Spalart-Allmaras, realizable k-epsilon, k-omega SST-LM (transition)
Physics MRF, cyclic / cyclicAMI, porosity, rotor-disk & fvOptions, wall functions, force/moment coefficients
Schemes Gauss upwind / linearUpwind / limitedLinear / vanLeer / MUSCL, bounded div, corrected (non-orthogonal) laplacian
BCs the standard incompressible set (fixedValue, zeroGradient, inletOutlet, freestream, slip, symmetry, wall functions, ...)
I/O standard OpenFOAM case in, standard time directories out; ASCII & binary mesh

Legend: ✓ supported & validated · ✗ not yet.

Solver & algorithm

feature status
SIMPLE / SIMPLEC pressure-velocity coupling ✓
Momentum: div(phi,U) − laplacian(nuEff,U) − div(devReff) (full incompressible stress) ✓
Pressure reference handling (closed domains, all-Neumann, fixedFluxPressure) ✓
Under-relaxation, residualControl convergence ✓
Non-orthogonal correction in the Laplacian (corrected) ✓
nNonOrthogonalCorrectors > 0 (extra pressure correctors) ✓ (with a corrected laplacian scheme)

Turbulence (RAS), 5 models, all validated vs OpenFOAM v2412

model notes
laminar machine-precision vs OF
k-epsilon channel / pitzDaily / backward-facing-step, sub-1%
realizable k-epsilon coefficients read from dict
k-omega SST pitzDaily settled U 0.10% / p 0.18% / k 0.09%
Spalart-Allmaras NACA0012 airfoil; lift within ~1% of OF
k-omega SST-LM (Langtry-Menter transition) transitional airfoil; transition captured
plain k-omega, RNG k-epsilon, LaunderSharma, RSM, LES ✗ not yet

Model coefficients are read from turbulenceProperties (defaults match OpenFOAM exactly). Wall functions: nutkWallFunction, nutUSpaldingWallFunction, and the standard k/epsilon/omega wall functions.

Boundary conditions

The standard incompressible set: fixedValue, zeroGradient, noSlip, slip, symmetry / symmetryPlane, inletOutlet, outletInlet, pressureInletOutletVelocity, freestream / freestreamPressure, fixedFluxPressure, uniformFixedValue, atmBoundaryLayerInlet*, and the wall-function BCs. cyclic and cyclicAMI are supported as coupled interfaces. Unsupported BCs are rejected by name at start-up.

Discretization schemes (fvSchemes)

category supported
div(phi,U) Gauss upwind, linearUpwind, linearUpwindV, LUST, limitedLinear, vanLeer, MUSCL, bounded
div(phi,k|epsilon|omega|nuTilda) upwind, limitedLinear
gradient Gauss linear, cellLimited
laplacian / snGrad Gauss linear corrected (non-orthogonal), limited
interpolation linear

The vector-limited limitedLinearV falls back to its scalar form; leastSquares gradient and cellLimited-corrected combinations are not yet available.

Physics & function objects

feature status
MRF (multiple reference frames) ✓ validated (laminar + turbulent)
cyclic / cyclicAMI interfaces (incl. turbulence transport across) ✓
Porosity (Darcy-Forchheimer) ✓
fvOptions (rotorDiskSource, meanVelocityForce, velocityDamping, ...) ✓ (subset)
forces / forceCoeffs (Cd, Cl, Cm) ✓ validated (airfoil Cl within ~1% of OF)
yPlus, wallShearStress, Q, vorticity, mag(U) writers ✓
general fvOptions framework, arbitrary function objects ✗ (subset only)

Mesh & I/O

  • Reads OpenFOAM polyMesh, ASCII or binary, gzipped (*.gz) or plain.
  • Reads stock dictionaries and $macro expansions.
  • Writes standard time directories, post-process with paraFoam / postProcess exactly as usual.
  • True 3D and 2D (empty-patch) meshes; validated on structured, graded, and snappyHexMesh meshes.

If you hit an unsupported model, BC, or scheme, brae stops with a clear message naming it, it never silently substitutes something else. See roadmap.md for what is on the roadmap.