OpenFOAM Case Generator

ANSYS MESH → OPENFOAM BC SETUP
01 SOLVER
02 MESH
03 QUALITY
04 BOUNDARIES
05 NUMERICS
06 GENERATE
07 TOOLS
08 FORMULAE
SOLVER SELECTION
SOLVER DETAIL
FLUID PROPERTIES
🌐 ISA STANDARD ATMOSPHERE CALCULATOR ▶ expand
🌡 SUTHERLAND VISCOSITY CALCULATOR (AIR) ▶ expand
TURBULENCE INLET CALCULATOR
Calculate k, ε/ω from turbulence intensity and length scale
k—
ε—
ω—
νt—
WORKFLOW GUIDE
1.Mesh geometry in ANSYS Meshing, name boundaries as Named Selections
2.Export: File → Export → Mesh → Fluent Input File (.msh)
3.Convert: fluent3DMeshToFoam mesh.msh
or: ansysToFoam mesh.msh -scale 0.001
4.Upload .msh in Tab 2 to auto-import patch names
5.Configure BCs in Tab 3, numerics in Tab 4
6.Download ZIP → extract to case folder
7.Run: checkMesh && simpleFoam (or relevant solver)
IMPORT MESH FILE
Supports Fluent ASCII .msh files and OpenFOAM constant/polyMesh/boundary files. Patch names are extracted automatically.
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Drop .msh or boundary file here, or click to browse
Fluent .msh or OpenFOAM polyMesh/boundary
IMPORT FROM EXISTING CASE
ADD PATCH MANUALLY
PATCH LIST 0 patches
No patches defined yet.
Import a mesh file or add manually.
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No mesh imported yet.
Import a .msh file in Tab 2 to run automatic quality analysis.
FAR-FIELD BC CALCULATOR (External Aero)
BC CONSISTENCY VALIDATOR
Checks for common BC configuration errors before generating files.
Set boundary conditions for each imported patch across all flow fields. Hover over any BC type option to see what it does.
CONTROL DICT
FV SCHEMES PRESET
FV SOLUTION — SIMPLE/PIMPLE
RELAXATION PRESETS
STABILITY & SAFEGUARDS
PARALLEL DECOMPOSITION
COURANT NUMBER ESTIMATOR
Co = U·Δt/Δx — must be < 1 for explicit schemes. PIMPLE allows Co > 1 with inner loops.
THERMOPHYSICAL PROPERTIES
For compressible/buoyant solvers. Inputs are taken from Tab 1 Fluid Properties.
fvOPTIONS GENERATOR
Add momentum sources, MRF rotating zones, porosity, and explicit heat sources. Generated into system/fvOptions.
FILE TREE
Select a file to preview
Select a file from the tree to preview its content.
CASE COMPARISON & SNAPSHOTS
Save the current configuration as a named snapshot to compare with other setups.
Save at least 2 snapshots to compare.
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CASE VALIDATOR
Deep syntax & logic checks
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VERSION COMPAT
Cross-version keyword checker
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RUN SCRIPT
Allrun / HPC job generator
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MEMORY EST.
RAM per core estimator
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SCALING EFF.
Parallel speedup & Amdahl
OPENFOAM TOOLS v2.0
CASE FILE VALIDATOR
Syntax · BC logic · dimensions · patch consistency · required keywords
CURRENT FILE
Upload a ZIP to view files
CORRECTED FILE
Auto-corrections appear here
TURBULENCE INLET — FORMULAE
Turbulent Kinetic Energy k
k = 1.5 · (Uref · Tu / 100)²
Derived from the definition of turbulence intensity Tu = u'/U, assuming isotropic turbulence where k = (3/2)·u'².
Turbulent Dissipation Rate ε
ε = Cμ0.75 · k1.5 / Lmix
Standard equilibrium assumption from k-ε model. Cμ = 0.09 (constant). Lmix is the turbulent length scale (mixing length).
Specific Dissipation Rate ω
ω = k0.5 / (Cμ0.25 · Lmix)
Derived from ω = ε / (Cμ·k). Used by kOmegaSST and kOmega models.
Turbulent Viscosity νt
νt = Cμ · k² / ε
Boussinesq hypothesis: turbulent stresses modelled via eddy viscosity. Used as initial/inlet value for nut field.
Spalart-Allmaras Modified Viscosity ν̃
ν̃ = 5 · ν
Common initialisation heuristic for farfield/inlet. ν is the molecular kinematic viscosity. Typically 3–5× ν for inlet.
WALL TREATMENT — ASSUMPTIONS
High-Re Wall Functions (y⁺ 30–300)
u⁺ = (1/κ) · ln(E · y⁺)
Log-law region. κ ≈ 0.41 (von Kármán constant), E ≈ 9.8 (roughness constant for smooth walls). The first cell centroid must sit in the log-law layer. Wall functions (kqRWallFunction, epsilonWallFunction, omegaWallFunction, nutkWallFunction) apply modified BCs to bridge the viscous sublayer.
Low-Re Resolve BL (y⁺ ≈ 1)
y⁺ = uτ · y / ν  ,  uτ = √(τw/ρ)
The viscous sublayer (y⁺ < 5) is fully resolved. No wall function model is used; exact no-slip BCs are applied (fixedValue U=0, fixedValue k=0, nutLowReWallFunction). Requires much finer near-wall mesh.
Wall y⁺ Target Estimator
Δy = y⁺ · ν / uτ    where    uτ ≈ 0.036 · U · Re-1/7
Flat-plate approximation for first-cell height. ReL = U·L/ν. For complex geometry, use the full CFD result from a coarse run to estimate uτ.
BOUNDARY CONDITION — PHYSICS NOTES
fixedValue
Dirichlet condition. The field value is pinned to the specified value at the boundary face. Used for known inlet velocity, temperature, or pressure.
zeroGradient
Neumann condition: ∂φ/∂n = 0. The field is extrapolated with zero normal gradient — value at boundary equals the adjacent cell value. Standard for outlets and walls for pressure.
inletOutlet
Mixed condition: zeroGradient when flow exits, fixedValue (inletValue) when flow enters through this patch. Prevents reverse-flow instabilities at outlets. Essential for outlets in recirculating flows.
totalPressure
p0 = p + ½ρU²
Specifies total (stagnation) pressure. Adjusts static pressure based on local velocity. Useful for pressure-inlet BCs where total pressure is known (e.g. fan curves, nozzle entries).
surfaceNormalFixedValue
Velocity is applied normal to the boundary face. Magnitude is given (negative = into domain). Avoids specifying Cartesian components when patch orientation is complex.
flowRateInletVelocity
Computes face-normal velocity from a volumetric flow rate Q (m³/s) divided by face area. Ensures a specified mass/volume flux regardless of patch area or shape.
pressureInletOutletVelocity
For pressure-driven outlets: uses zeroGradient for outflow, and flux-corrected fixedValue for inflow to prevent reverse-flow numerical instability.
fixedFluxPressure
Adjusts pressure gradient to match the prescribed velocity flux at the boundary (Neumann-type). Used at walls for p_rgh in buoyant/interFoam solvers to avoid over-constraining pressure.
turbulentIntensityKineticEnergyInlet
k = 1.5 · (I · |U|)²
Computes k from turbulence intensity I (0–1) and local velocity magnitude. OpenFOAM BC that handles the turbulent energy inlet automatically based on current U field.
symmetryPlane / empty / wedge / cyclic
symmetryPlane: mirror BC — zero normal gradient and zero normal velocity. empty: 2D geometry — suppresses solve in that direction. wedge: axisymmetric geometry — special treatment at sector boundaries. cyclic: periodic — matching patch pairs share values across the interface.
NUMERICAL SCHEMES — ASSUMPTIONS
First-order Upwind (Robust preset)
φf = φupwind cell
O(h) truncation error. Introduces significant numerical diffusion. Stable for poor meshes or high-skewness geometries. Used to initialize convergence before switching to higher order.
Linear Upwind (Accurate preset)
φf = φP + ψ(∇φ)P · dPf
O(h²) — second-order upwind with gradient reconstruction. ψ is the slope limiter (gradLimiter). Balances accuracy and boundedness. Recommended for production RANS runs.
Gauss Linear (High-Order preset)
φf = ½(φP + φN)
Central differencing — O(h²) but unbounded. Prone to oscillations on non-orthogonal or stretched meshes. Only appropriate for well-structured, high-quality meshes. Can be used for LES.
nNonOrthogonalCorrectors
Corrects the pressure Laplacian for non-orthogonal mesh faces. For max non-orthogonality <70°: 0 corrections. 70–85°: 1–2 corrections. >85°: 3+ corrections. Each correction adds one additional pressure solve per SIMPLE iteration.
Relaxation Factors
φnew = α·φiter + (1−α)·φold
Under-relaxation stabilises the SIMPLE loop. Typical values: p=0.3, U=0.7, k/ω=0.5. Tighter (smaller) factors improve stability at cost of slower convergence. α=1 = no relaxation.
GAMG Solver (pressure)
Geometric-Algebraic Multi-Grid. Solves coarse-to-fine grid hierarchy — O(N) complexity. Fastest for large structured meshes. agglomerator: faceAreaPair (default). smoother: GaussSeidel.