Draft. This manual is new and still growing. If something here does not match what you see in the software, the software is right — tell us and we will fix the page.

Physics

Where it is

Not a setup-tree node. Embedded in the application.

Controls

Phases (…)

Surface tension

Control: value (ValueField)
Unit: N/m
Default: 0.07
Bound to: CaseState.surfaceTension
Writes: transportProperties
Value modes: none (plain entry)
Shown when: CaseState.nPhaseCase

Applied to every pair of phases alike - the bundled tutorials use the same one number across all of theirs too.

Interface

Capture scheme

Control: choice (ComboRow)
Default: isoAdvector
Bound to: CaseState.interfaceScheme
Options: isoAdvector, MULES
Writes: fvSolution/solvers/alpha
Shown when: CaseState.twoPhaseVof

The in-app guidance depends on the case:

Geometric reconstruction; the interface stays inside about one cell. Runs interIsoFoam.
Algebraic compression. More forgiving on a poor mesh, and the interface smears over several cells. Runs interFoam.

Compression

Control: value (ValueField)
Default: 1.0
Bound to: CaseState.cAlpha
Value modes: none (plain entry)
Shown when: CaseState.twoPhaseVof && CaseState.interfaceScheme === "MULES"

cAlpha. 1 is the usual value; 0 turns compression off entirely.

Interface correctors

Control: value (ValueField)
Default: 2
Bound to: CaseState.nAlphaCorr
Writes: fvSolution/solvers/alpha
Value modes: none (plain entry)
Shown when: CaseState.twoPhaseVof

How many times alpha is corrected within a step.

Alpha sub-cycles

Control: value (ValueField)
Default: 1
Bound to: CaseState.nAlphaSubCycles
Writes: fvSolution/alpha/nAlphaSubCycles
Value modes: none (plain entry)
Shown when: CaseState.twoPhaseVof

How many smaller steps the phase fraction is advanced in per time step. More sub-cycles keep alpha inside [0, 1] when the interface is moving fast, at a little more cost.

Semi-implicit MULES

Control: on/off (ToggleRow)
Default: true
Bound to: CaseState.mulesSemiImplicit
Shown when: CaseState.twoPhaseVof

On: solve alpha implicitly, then apply one limited explicit correction - faster, and it tolerates a bigger step. Off: fully explicit, which bounds alpha harder. Turn it off if Max(alpha) drifts above 1.

Isotropic compression

Control: value (ValueField)
Default: 0.0
Bound to: CaseState.icAlpha
Writes: fvSolution/alpha/icAlpha
Value modes: none (plain entry)
Shown when: CaseState.twoPhaseVof

icAlpha. 0 compresses the interface only along its normal; 1 compresses in every direction. A little - 0.25 - stops the compression term carving the interface into steps on a hex mesh.

Outer correctors

Control: value (ValueField)
Bound to: CaseState.nOuterCorrectors
Writes: fvSolution/PIMPLE/nOuterCorrectors
Value modes: none (plain entry)
Shown when: CaseState.twoPhaseVof && !CaseState.steady

nOuterCorrectors. How many times pressure and velocity are coupled within a step. Two is usual; raise it when a violent free surface will not hold coupling in two.

Limit velocity

Control: on/off (ToggleRow)
Default: true
Bound to: CaseState.velocityLimitEnabled
Shown when: CaseState.twoPhaseVof

Writes a limitVelocity fvOption capping |U|. It is a no-op wherever the solution is physical and a clamp on the one rogue cell a plunging free surface can produce - which otherwise takes the pressure field and the time step with it.

Velocity limit

Control: value (ValueField)
Unit: m/s
Default: 500
Bound to: CaseState.velocityLimit
Writes: fvOptions/limitU/max
Value modes: none (plain entry)
Shown when: CaseState.twoPhaseVof && CaseState.velocityLimitEnabled

The ceiling on |U|. Set it well above anything the case should physically reach - the point is to catch a cell that has gone wrong, not to shape the solution.

Inner correctors

Control: value (ValueField)
Bound to: CaseState.nCorrectors
Writes: fvSolution/PIMPLE/nCorrectors
Value modes: none (plain entry)
Shown when: CaseState.twoPhaseVof && !CaseState.steady

nCorrectors. How many times the pressure equation is re-solved within one outer iteration - the second knob after the outer correctors when a case will not hold continuity.

Momentum predictor

Control: on/off (ToggleRow)
Bound to: CaseState.momentumPredictor
Shown when: CaseState.twoPhaseVof

Solves the momentum equation before the first pressure correction. Turning it OFF is a standard remedy for a high-density-ratio case that will not hold that first correction - which is why the compressible VoF solvers ship with it off.

Correct fluxes

Control: on/off (ToggleRow)
Default: false
Bound to: CaseState.correctPhi
Shown when: CaseState.twoPhaseVof

correctPhi. On a moving mesh the face fluxes carried over from the previous position no longer satisfy continuity on the new one; this is the step that makes them. Defaults on exactly when the mesh moves.

Iso face tolerance

Control: value (ValueField)
Default: 1e-10
Bound to: CaseState.isoFaceTol
Value modes: none (plain entry)
Shown when: CaseState.interfaceScheme === "isoAdvector"

isoAdvector's own tolerance on where it places the interface inside a cell.

Surface cell tolerance

Control: value (ValueField)
Default: 1e-6
Bound to: CaseState.surfCellTol
Value modes: none (plain entry)
Shown when: CaseState.interfaceScheme === "isoAdvector"

isoAdvector's own tolerance on where it places the interface inside a cell.

Alpha bound passes

Control: value (ValueField)
Default: 3
Bound to: CaseState.nAlphaBounds
Value modes: none (plain entry)
Shown when: CaseState.interfaceScheme === "isoAdvector"

isoAdvector's own tolerance on where it places the interface inside a cell.

Interface Courant limit

Control: value (ValueField)
Default: 0.5
Bound to: CaseState.maxAlphaCourant
Value modes: none (plain entry)
Shown when: CaseState.twoPhaseVof && !CaseState.steady

maxAlphaCo. Tighter than the flow limit, because the interface is what the time step has to resolve.

Acoustic Courant limit

Control: value (ValueField)
Default: 50
Bound to: CaseState.maxAcousticCourant
Writes: controlDict/maxAcousticCo
Value modes: none (plain entry)
Shown when: CaseState.solverIs("cavitatingFoam") && !CaseState.steady

maxAcousticCo. Both phases are compressible here, so sound is the fastest thing in the domain and the flow limit does not see it. The moving-mesh build needs about a tenth of the static one's.

Bed packing threshold

Control: value (ValueField)
Default: 0.1
Bound to: CaseState.bedFractionThreshold
Value modes: none (plain entry)
Shown when: CaseState.physicsFamily === "driftFlux"

The dispersed fraction above which a cell counts as settled bed rather than suspension. The bed-height monitor reports the highest cell that passes it.

Fill to

Control: value (ValueField)
Unit: m
Default: 0.0
Bound to: CaseState.fillLevel
Writes: setFieldsDict
Value modes: none (plain entry)
Shown when: CaseState.twoPhaseVof && CaseState.fillEnabled

Height on the up axis, in case coordinates. Applying it makes a box from the domain floor to that height, and a subdomain that starts … inside it.

Make it a box and a subdomain

Control: action (ToolButton2)
Shown when: CaseState.twoPhaseVof && CaseState.fillEnabled
Enabled when: CaseState.fillLevel > 0

Width

Control: value (ValueField)
Unit: m
Default: 0.076
Bound to: CaseState.cavityWidth
Value modes: none (plain entry)
Shown when: CaseState.vesselKind === "cavity"

The gap between the hot and cold faces - the length scale the Rayleigh number is defined on.

Height

Control: value (ValueField)
Unit: m
Default: 2.18
Bound to: CaseState.cavityHeight
Value modes: none (plain entry)
Shown when: CaseState.vesselKind === "cavity"

Depth

Control: value (ValueField)
Unit: m
Default: 0.52
Bound to: CaseState.cavityDepth
Value modes: none (plain entry)
Shown when: CaseState.vesselKind === "cavity" && !CaseState.twoDimensional

Ignored on a two-dimensional case, where the thin direction is one cell by construction regardless of this number.

Hot face

Control: value (ValueField)
Unit: K
Default: 307.75
Bound to: CaseState.cavityHotT
Value modes: none (plain entry)
Shown when: CaseState.sealedVessel

With this equal to the cold face nothing moves, and a natural-convection run reports a still box.

Cold face

Control: value (ValueField)
Unit: K
Default: 288.15
Bound to: CaseState.cavityColdT
Value modes: none (plain entry)
Shown when: CaseState.sealedVessel

Across the pair

Control: value (ValueField)
Unit: V
Default: 1000
Bound to: CaseState.electrodeVolts
Value modes: none (plain entry)
Shown when: CaseState.vesselKind === "electrodes"

The potential difference between the two plates. At zero there is no field and the solver has nothing to compute.

Sparger velocity

Control: value (ValueField)
Unit: m/s
Default: 0.1
Bound to: CaseState.spargerVelocity
Value modes: none (plain entry)
Shown when: CaseState.vesselKind === "column"

Superficial gas velocity in through the floor. This is what makes the plume; at zero the column does nothing.

Engine

Speed

Control: value (ValueField)
Unit: rpm
Default: 1500
Bound to: CaseState.engineRpm
Value modes: none (plain entry)
Shown when: CaseState.isEngineSolver

Turbulence box

Forcing amplitude

Control: value (ValueField)
Default: 0.090295
Bound to: CaseState.dnsUOsigma
Value modes: none (plain entry)
Shown when: CaseState.periodicBox

The Uhlenbeck-Ornstein forcing that holds the turbulence up. Without it the box decays to rest.

Forcing time constant

Control: value (ValueField)
Default: 0.81532
Bound to: CaseState.dnsUOalpha
Value modes: none (plain entry)
Shown when: CaseState.periodicBox

Forced wavenumbers, from

Control: value (ValueField)
Default: 7
Bound to: CaseState.dnsUOKlower
Value modes: none (plain entry)
Shown when: CaseState.periodicBox

The band the forcing is applied over, in wavenumbers.

to

Control: value (ValueField)
Default: 10
Bound to: CaseState.dnsUOKupper
Value modes: none (plain entry)
Shown when: CaseState.periodicBox

Initial spectrum peak

Control: value (ValueField)
Default: 10
Bound to: CaseState.dnsEa
Value modes: none (plain entry)
Shown when: CaseState.periodicBox

boxTurb seeds the starting field from an energy spectrum: this is its peak, and the wavenumber below is where it peaks.

at wavenumber

Control: value (ValueField)
Default: 5
Bound to: CaseState.dnsK0
Value modes: none (plain entry)
Shown when: CaseState.periodicBox

Wall film

Film density

Control: value (ValueField)
Unit: kg/m³
Default: 100.0
Bound to: CaseState.filmLiquidRho
Value modes: none (plain entry)
Shown when: CaseState.finiteArea

Film viscosity

Control: value (ValueField)
Unit: m²/s
Default: 1e-3
Bound to: CaseState.filmLiquidNu
Value modes: none (plain entry)
Shown when: CaseState.finiteArea

Gas density

Control: value (ValueField)
Unit: kg/m³
Default: 1.0
Bound to: CaseState.filmGasRho
Value modes: none (plain entry)
Shown when: CaseState.finiteArea

Gas viscosity

Control: value (ValueField)
Unit: m²/s
Default: 0.0
Bound to: CaseState.filmGasNu
Value modes: none (plain entry)
Shown when: CaseState.finiteArea

Surface tension

Control: value (ValueField)
Unit: N/m
Default: 0.1
Bound to: CaseState.filmSigma
Value modes: none (plain entry)
Shown when: CaseState.finiteArea

What holds a rivulet together rather than letting it spread.

Minimum thickness

Control: value (ValueField)
Unit: m
Default: 1e-10
Bound to: CaseState.filmMinThickness
Value modes: none (plain entry)
Shown when: CaseState.finiteArea

The floor the film is not allowed to thin below, which is what keeps a dry patch from dividing by zero.

Waves

Wave model

Control: choice (ComboRow)
Default: StokesII
Bound to: CaseState.waveModel
Options: StokesI, StokesII, StokesV, cnoidal, Grimshaw, streamFunction, JONSWAP (from CaseState.waveModels)
Writes: waveProperties
Shown when: root.fam === "marine"

Significant height Hs

Control: value (ValueField)
Unit: m
Default: 2.0
Bound to: CaseState.waveHs
Writes: waveProperties
Value modes: none (plain entry)
Shown when: root.fam === "marine"

Peak period Tp

Control: value (ValueField)
Unit: s
Default: 8.0
Bound to: CaseState.waveTp
Writes: waveProperties
Value modes: none (plain entry)
Shown when: root.fam === "marine"

Peak enhancement γ

Control: value (ValueField)
Default: 3.3
Bound to: CaseState.waveGamma
Writes: waveProperties
Value modes: none (plain entry)
Shown when: root.fam === "marine"

Components

Control: value (ValueField)
Default: 40
Bound to: CaseState.waveComponentCount
Writes: waveProperties
Value modes: none (plain entry)
Shown when: root.fam === "marine"

Heading

Control: value (ValueField)
Unit: °
Default: 0.0
Bound to: CaseState.waveAngleDeg
Writes: waveProperties
Value modes: none (plain entry)
Shown when: root.fam === "marine"

Water depth

Control: value (ValueField)
Unit: m
Default: 10.0
Bound to: CaseState.waterDepth
Writes: waveProperties
Value modes: none (plain entry)
Shown when: root.fam === "marine"

Wave height

Control: value (ValueField)
Unit: m
Default: 1.0
Bound to: CaseState.waveHeight
Writes: waveProperties
Value modes: none (plain entry)
Shown when: root.fam === "marine"

Period

Control: value (ValueField)
Unit: s
Default: 6.0
Bound to: CaseState.wavePeriod
Writes: waveProperties
Value modes: none (plain entry)
Shown when: root.fam === "marine"

Interphase forces

Dispersed phase

Control: choice (ComboRow)
Default: air
Bound to: CaseState.dispersedPhase
Writes: phaseProperties
Shown when: root.fam === "euler" && !CaseState.nPhaseCase

The one that exists as bubbles, drops or particles inside the other.

Dispersed diameter

Control: value (ValueField)
Unit: m
Default: 0.003
Bound to: CaseState.dispersedDiameter
Writes: phaseProperties/diameterModel
Value modes: none (plain entry)
Shown when: root.fam === "euler" && !CaseState.nPhaseCase

Drag

Control: choice (ComboRow)
Default: SchillerNaumann
Bound to: CaseState.dragModel
Options: SchillerNaumann, WenYu, GidaspowErgunWenYu, Ergun, Lain (from CaseState.dragModels)
Writes: phaseProperties/drag
Shown when: root.fam === "euler"

Not optional. Without drag the phases pass through each other.

Lift

Control: choice (ComboRow)
Default: none
Bound to: CaseState.liftModel
Options: none, constantCoefficient, Tomiyama, Moraga, LegendreMagnaudet (from CaseState.liftModels)
Writes: phaseProperties/lift
Shown when: root.fam === "euler"

Sideways force on a bubble in a shear layer. Decides whether bubbles migrate to the wall or the core.

Virtual mass

Control: value (ValueField)
Default: 0.5
Bound to: CaseState.virtualMassCoeff
Value modes: none (plain entry)
Shown when: root.fam === "euler"

Cvm. 0.5 for a sphere.

Initial dispersed fraction

Control: value (ValueField)
Default: 0.0
Bound to: CaseState.dispersedAlpha
Value modes: none (plain entry)
Shown when: root.fam === "euler"

Particles

Two-way coupled

Control: on/off (ToggleRow)
Default: false
Bound to: CaseState.twoWayCoupled
Writes: kinematicCloudProperties/solution/coupled
Shown when: root.fam === "lagrangian"

Off, the particles are carried by the flow and do not affect it - far cheaper, and right whenever the loading is light. On runs DPMFoam, which feeds the particle momentum back into the fluid.

Carrier phase name

Control: value (ValueField)
Default: air
Bound to: CaseState.continuousPhaseName
Writes: kinematicCloudProperties/solution/continuousPhaseName
Value modes: none (plain entry)
Shown when: root.fam === "lagrangian" && CaseState.twoWayCoupled

DPMFoam names the carrier fields after it, so the velocity is U.… rather than U.

Injection

Control: choice (ComboRow)
Default: patchInjection
Bound to: CaseState.injectionModel
Options: patchInjection, coneInjection, manualInjection (from CaseState.injectionModels)
Writes: kinematicCloudProperties/injectionModels
Shown when: root.fam === "lagrangian"

Injection patch

Control: choice (ComboRow)
Bound to: CaseState.effectiveInjectionPatch
Shown when: root.fam === "lagrangian" && CaseState.injectionModel === "patchInjection"

Breakup model

Control: choice (ComboRow)
Default: ReitzDiwakar
Bound to: CaseState.breakupModel
Options: none, ReitzDiwakar, ReitzKHRT (from CaseState.breakupModels)
Writes: sprayCloudProperties/subModels/breakupModel
Shown when: CaseState.buildsSprayCloud

Secondary breakup of an injected droplet into smaller ones as it is dragged through the carrier. Every bundled spray tutorial uses a real model here, never "none".

Size distribution

Control: choice (ComboRow)
Default: fixedValue
Bound to: CaseState.sizeDistribution
Options: fixedValue, uniform, RosinRammler (from CaseState.sizeDistributions)
Shown when: root.fam === "lagrangian"

The usual description of a spray or a milled powder.

Particle density

Control: value (ValueField)
Unit: kg/m³
Default: 1000
Bound to: CaseState.particleRho
Writes: kinematicCloudProperties
Value modes: none (plain entry)
Shown when: (root.fam === "lagrangian" || root.fam === "spray" || root.fam === "reacting")

Diameter

Control: value (ValueField)
Unit: m
Default: 1.0e-4
Bound to: CaseState.particleDiameter
Writes: kinematicCloudProperties
Value modes: none (plain entry)
Shown when: (root.fam === "lagrangian" || root.fam === "spray" || root.fam === "reacting")

Injection temperature

Control: value (ValueField)
Unit: K
Default: 320
Bound to: CaseState.parcelTemperature
Writes: kinematicCloudProperties
Value modes: none (plain entry)
Shown when: (root.fam === "lagrangian" || root.fam === "spray" || root.fam === "reacting")

Minimum diameter

Control: value (ValueField)
Unit: m
Default: 1.0e-5
Bound to: CaseState.particleDMin
Writes: kinematicCloudProperties
Value modes: none (plain entry)
Shown when: (root.fam === "lagrangian" || root.fam === "spray" || root.fam === "reacting")

Maximum diameter

Control: value (ValueField)
Unit: m
Default: 5.0e-4
Bound to: CaseState.particleDMax
Writes: kinematicCloudProperties
Value modes: none (plain entry)
Shown when: (root.fam === "lagrangian" || root.fam === "spray" || root.fam === "reacting")

Distribution exponent

Control: value (ValueField)
Default: 2.0
Bound to: CaseState.rosinRammlerN
Writes: kinematicCloudProperties
Value modes: none (plain entry)
Shown when: (root.fam === "lagrangian" || root.fam === "spray" || root.fam === "reacting")

Mass flow

Control: value (ValueField)
Unit: kg/s
Default: 0.01
Bound to: CaseState.injectionMassFlow
Writes: kinematicCloudProperties
Value modes: none (plain entry)
Shown when: (root.fam === "lagrangian" || root.fam === "spray" || root.fam === "reacting")

Injection time

Control: value (ValueField)
Unit: s
Default: 1.0
Bound to: CaseState.injectionDuration
Writes: kinematicCloudProperties
Value modes: none (plain entry)
Shown when: (root.fam === "lagrangian" || root.fam === "spray" || root.fam === "reacting")

Injection speed

Control: value (ValueField)
Unit: m/s
Default: 10.0
Bound to: CaseState.injectionSpeed
Writes: kinematicCloudProperties
Value modes: none (plain entry)
Shown when: (root.fam === "lagrangian" || root.fam === "spray" || root.fam === "reacting")

Parcels per second

Control: value (ValueField)
Default: 1000
Bound to: CaseState.parcelsPerSecond
Writes: kinematicCloudProperties
Value modes: none (plain entry)
Shown when: (root.fam === "lagrangian" || root.fam === "spray" || root.fam === "reacting")

Drag law

Control: choice (ComboRow)
Default: sphereDrag
Bound to: CaseState.parcelDrag
Options: sphereDrag, nonSphereDrag, distortedSphereDrag
Shown when: root.fam === "lagrangian"

Max packing (alphaMax)

Control: value (ValueField)
Default: 0.62
Bound to: CaseState.dpmAlphaMax
Writes: kinematicCloudProperties/constantProperties
Value modes: none (plain entry)
Shown when: (root.fam === "lagrangian" && CaseState.cloudIsCoupled)

Young's modulus

Control: value (ValueField)
Unit: Pa
Default: 1e8
Bound to: CaseState.dpmYoungsModulus
Writes: kinematicCloudProperties/constantProperties
Value modes: none (plain entry)
Shown when: (root.fam === "lagrangian" && CaseState.cloudIsCoupled)

Poisson's ratio

Control: value (ValueField)
Default: 0.35
Bound to: CaseState.dpmPoissonsRatio
Writes: kinematicCloudProperties/constantProperties
Value modes: none (plain entry)
Shown when: (root.fam === "lagrangian" && CaseState.cloudIsCoupled)

Combustion

Combustion model

Control: choice (ComboRow)
Default: PaSR
Bound to: CaseState.combustionModel
Options: laminar, PaSR, EDC, infinitelyFastChemistry, diffusion (from CaseState.combustionModels)
Writes: combustionProperties
Shown when: root.fam === "reacting"

Solve chemistry

Control: on/off (ToggleRow)
Default: true
Bound to: CaseState.chemistryActive
Writes: chemistryProperties/chemistry
Shown when: root.fam === "reacting"

Chemistry solver

Control: choice (ComboRow)
Default: EulerImplicit
Bound to: CaseState.chemistrySolver
Options: EulerImplicit, ode, none (from CaseState.chemistrySolvers)
Shown when: root.fam === "reacting" && CaseState.chemistryActive

The in-app guidance depends on the case:

Stiff ODE integration. Slower and far more robust on a real mechanism.
Cheap and adequate for a few reactions.

Species

Control: value (ValueField)
Default: CH4 O2 CO2 H2O N2
Bound to: CaseState.speciesList
Writes: constant/reactions
Value modes: none (plain entry)
Shown when: root.fam === "reacting"

Space separated. Each becomes a mass fraction field in 0/.

Fuel

Control: choice (ComboRow)
Default: CH4
Bound to: CaseState.fuelSpecies
Shown when: root.fam === "reacting"

Oxidiser

Control: choice (ComboRow)
Default: O2
Bound to: CaseState.oxidiserSpecies
Shown when: root.fam === "reacting"

Inert

Control: choice (ComboRow)
Default: N2
Bound to: CaseState.inertSpecies
Shown when: root.fam === "reacting"

Initial temperature

Control: value (ValueField)
Unit: K
Default: 1000
Bound to: CaseState.ignitionTemperature
Writes: 0/T
Value modes: none (plain entry)
Shown when: root.fam === "reacting"

The whole domain starts here. Below the ignition temperature the chemistry integrates to no reaction and the run is an expensive way to mix two cold gases.

Radiation

Control: on/off (ToggleRow)
Default: false
Bound to: CaseState.radiationEnabled
Writes: constant/radiationProperties
Shown when: root.fam === "reacting" || root.fam === "buoyant" || root.fam === "cht"

The in-app guidance depends on the case:

P1 with a grey absorption coefficient. In a flame radiation carries a serious fraction of the heat away; outside one it is cost for nothing.
P1 with a grey absorption coefficient. Worth it once a surface is hot enough that radiation is a real fraction of its heat loss - a few hundred degrees and up - and cost for nothing well below that.

Radiation model

Control: choice (ComboRow)
Default: P1
Bound to: CaseState.radiationModel
Options: P1, View factor (from CaseState.radiationModels)
Writes: radiationProperties/radiationModel
Shown when: CaseState.radiationEnabled && (root.fam === "reacting" || root.fam === "buoyant")

The in-app guidance depends on the case:

Surface-to-surface exchange through a transparent medium: hot and cold walls seeing each other across clear air. The gas itself neither absorbs nor emits. Two extra steps run before the solve to build the exchange matrix.
A diffusion approximation for a medium that absorbs and emits - a flame's products, a sooty gas. Wrong for clear air between surfaces; choose View factor there.

Absorptivity

Control: value (ValueField)
Unit: 1/m
Default: 0.5
Bound to: CaseState.radiationAbsorptivity
Value modes: none (plain entry)
Shown when: CaseState.radiationEnabled && (root.fam === "reacting" || root.fam === "buoyant" || root.fam === "cht")

Emissivity

Control: value (ValueField)
Unit: 1/m
Default: 0.5
Bound to: CaseState.radiationEmissivity
Value modes: none (plain entry)
Shown when: CaseState.radiationEnabled && (root.fam === "reacting" || root.fam === "buoyant" || root.fam === "cht")

Wall emissivity

Control: value (ValueField)
Default: 1.0
Bound to: CaseState.wallEmissivity
Value modes: none (plain entry)
Shown when: CaseState.radiationEnabled && (root.fam === "reacting" || root.fam === "buoyant" || root.fam === "cht")

Solve every

Control: value (ValueField)
Unit: steps
Default: 10
Bound to: CaseState.radiationSolverFreq
Value modes: none (plain entry)
Shown when: CaseState.radiationEnabled && (root.fam === "reacting" || root.fam === "buoyant" || root.fam === "cht")

Radiating faces per wall

Control: value (ValueField)
Default: 30
Bound to: CaseState.viewFactorCoarsening
Value modes: none (plain entry)
Shown when: CaseState.radiationEnabled && (root.fam === "reacting" || root.fam === "buoyant" || root.fam === "cht")

Atmospheric boundary layer

Terrain

Control: choice (ComboRow)
Bound to: CaseState.terrainCategories
Options: Sea or coastal, Open flat country, Farmland with hedges, Suburban or industrial, Urban (from CaseState.terrainCategories)
Writes: 0/U/inlet/z0
Shown when: root.fam === "atmospheric"

Roughness length z₀

Control: value (ValueField)
Unit: m
Default: 0.03
Bound to: CaseState.aerodynamicRoughness
Writes: 0/U
Value modes: none (plain entry)
Shown when: root.fam === "atmospheric"

Reference speed

Control: value (ValueField)
Unit: m/s
Default: 10.0
Bound to: CaseState.ablReferenceSpeed
Writes: 0/U
Value modes: none (plain entry)
Shown when: root.fam === "atmospheric"

Reference height

Control: value (ValueField)
Unit: m
Default: 10.0
Bound to: CaseState.ablReferenceHeight
Writes: 0/U
Value modes: none (plain entry)
Shown when: root.fam === "atmospheric"

Ground level

Control: value (ValueField)
Unit: m
Default: 0.0
Bound to: CaseState.groundHeight
Writes: 0/U
Value modes: none (plain entry)
Shown when: root.fam === "atmospheric"

Coriolis force

Control: on/off (ToggleRow)
Default: false
Bound to: CaseState.coriolisEnabled
Writes: constant/fvOptions
Shown when: root.fam === "atmospheric" || root.fam === "shallowWater"

The Earth turning under the flow. Negligible over a building, not over a wind farm.

Latitude

Control: value (ValueField)
Unit: °
Default: 52.0
Bound to: CaseState.siteLatitude
Writes: constant/fvOptions
Value modes: none (plain entry)
Shown when: (root.fam === "atmospheric" || root.fam === "shallowWater") && CaseState.coriolisEnabled

Positive north. The Coriolis parameter goes to zero at the equator.

Plant canopy

Control: on/off (ToggleRow)
Default: false
Bound to: CaseState.plantCanopyEnabled
Writes: constant/fvOptions
Shown when: root.fam === "atmospheric"

A vegetation drag sink (atmPlantCanopyUSource), uniform over the whole domain rather than limited to a canopy layer near the ground - there is no zone editor for it yet, so a tall domain gets drag at every height, not only where the trees are.

Drag coefficient (Cd)

Control: value (ValueField)
Default: 0.2
Bound to: CaseState.canopyDragCoeff
Writes: 0/Cd, 0/LAD
Value modes: none (plain entry)
Shown when: (root.fam === "atmospheric" && CaseState.plantCanopyEnabled)

Leaf area density

Control: value (ValueField)
Unit: 1/m
Default: 1.0
Bound to: CaseState.canopyLeafAreaDensity
Writes: 0/Cd, 0/LAD
Value modes: none (plain entry)
Shown when: (root.fam === "atmospheric" && CaseState.plantCanopyEnabled)

Transported scalar

Field name

Control: value (ValueField)
Default: s
Bound to: CaseState.scalarName
Writes: 0/…
Value modes: none (plain entry)
Shown when: root.fam === "scalar"

Molecular diffusivity

Control: value (ValueField)
Unit: m²/s
Default: 1.0e-5
Bound to: CaseState.scalarDiffusivity
Writes: controlDict/functions
Value modes: none (plain entry)
Shown when: root.fam === "scalar"

Initial value

Control: value (ValueField)
Default: 0.0
Bound to: CaseState.scalarInitial
Writes: controlDict/functions
Value modes: none (plain entry)
Shown when: root.fam === "scalar"

Inlet value

Control: value (ValueField)
Default: 1.0
Bound to: CaseState.scalarInlet
Writes: controlDict/functions
Value modes: none (plain entry)
Shown when: root.fam === "scalar"

Turbulent diffusion

Control: on/off (ToggleRow)
Default: true
Bound to: CaseState.scalarTurbulentSchmidt
Shown when: root.fam === "scalar"

Adds nu_t/Sc_t to the molecular diffusivity. In a turbulent flow this is the term that actually spreads the scalar.

Turbulent Schmidt number

Control: value (ValueField)
Default: 0.7
Bound to: CaseState.turbulentSchmidt
Value modes: none (plain entry)
Shown when: root.fam === "scalar" && CaseState.scalarTurbulentSchmidt

Viscosity

Model

Control: choice (ComboRow)
Default: Newtonian
Bound to: CaseState.viscosityModel
Options: Newtonian, CrossPowerLaw, BirdCarreau, powerLaw, HerschelBulkley (from CaseState.viscosityModels)
Writes: transportProperties/transportModel
Shown when: ["incompressible", "vof", "marine", "cavitation", "miscible", "atmospheric", "scalar", "lagrangian", "srf"] .indexOf(root.fam) >= 0

Viscosity at zero shear

Control: value (ValueField)
Unit: m²/s
Default: 1.0e-03
Bound to: CaseState.nuMax
Writes: transportProperties
Value modes: none (plain entry)
Shown when: CaseState.viscosityModel === "Newtonian"

Viscosity at infinite shear

Control: value (ValueField)
Unit: m²/s
Default: 1.0e-06
Bound to: CaseState.nuMin
Writes: transportProperties
Value modes: none (plain entry)
Shown when: CaseState.viscosityModel === "Newtonian"

Ignition

Light the charge

Control: on/off (ToggleRow)
Default: true
Bound to: CaseState.ignitionEnabled
Shown when: CaseState.solvesPremixedFields

Off, the mixture never lights: b stays at 1 everywhere, and the flame front this family is run for does not exist. The case still runs, and reports an unburnt charge sitting still.

Kernel diameter

Control: value (ValueField)
Unit: m
Default: 0
Bound to: CaseState.ignitionDiameter
Value modes: none (plain entry)
Shown when: CaseState.solvesPremixedFields && CaseState.ignitionEnabled

The spark, at the middle of the domain.

Starts at

Control: value (ValueField)
Unit: s
Default: 0
Bound to: CaseState.ignitionStart
Value modes: none (plain entry)
Shown when: CaseState.solvesPremixedFields && CaseState.ignitionEnabled

Held for

Control: value (ValueField)
Unit: s
Default: 0.001
Bound to: CaseState.ignitionDuration
Value modes: none (plain entry)
Shown when: CaseState.solvesPremixedFields && CaseState.ignitionEnabled

Long enough for the kernel to grow past the spark, and no longer.

Spark strength

Control: value (ValueField)
Default: 2
Bound to: CaseState.ignitionStrength
Writes: combustionProperties/ignitionSites
Value modes: none (plain entry)
Shown when: CaseState.solvesPremixedFields && CaseState.ignitionEnabled

How hard the kernel is driven. Too weak and the charge does not light; too strong and the thermo cannot invert the temperature it produces. Each solver is set to its own tutorial's value when it is chosen, and this overrides that.

Fuel inlet speed

Control: value (ValueField)
Unit: m/s
Default: 1.0
Bound to: CaseState.burnerFuelVelocity
Writes: 0/U
Value modes: none (plain entry)
Shown when: CaseState.vesselKind === "burner"

The centre slot. Its ratio to the air speed is what anchors the flame or blows it off.

Air inlet speed

Control: value (ValueField)
Unit: m/s
Default: 0.5
Bound to: CaseState.burnerAirVelocity
Writes: 0/U
Value modes: none (plain entry)
Shown when: CaseState.vesselKind === "burner"

The two outer slots, co-flowing with the fuel.

Pressure across the orifice

Control: value (ValueField)
Unit: Pa
Default: 2e5
Bound to: CaseState.throttleDeltaP
Value modes: none (plain entry)
Shown when: CaseState.vesselKind === "throttle"

What drives the flow, and what decides whether it cavitates: the dynamic head this buys has to take the throat below the vapour pressure. At zero nothing moves.

Saturation temperature

Control: value (ValueField)
Unit: K
Default: 373.15
Bound to: CaseState.saturationTemperature
Value modes: none (plain entry)
Shown when: root.fam === "cavitation"

Where the liquid boils at the case's pressure. The condensation and evaporation solvers drive their phase change off it.