Reference / Input deck / solver / equations

equations

The equations solved, and their turbulence and transport models

type precondition turbulencerequired›correction correction limiter gradient limiter type gradient limiter max second order non orthogonal angle central blend solve energyenergy variableadvanced base stateadvanced›theta perturbationadvanced›buoyancy diagnosticsadvanced velocity perturbationadvanced›geostrophic windadvanced sponge layeradvanced›

type

not set by default

The form of the flow equations to solve: inviscid Euler, viscous Navier–Stokes with no turbulence model, Reynolds-averaged Navier–Stokes (RANS) or large-eddy simulation (LES).

Options

Value	What it does
euler	Use the Euler flow equations in the simulation. These are compressible, inviscid flow equations.
viscous	Use the viscous flow equations. These are compressible, viscid flow equations which do not model turbulence.
rans	Use the RANS (Reynolds-Averaged Navier-Stokes) equations in the simulation. These are compressible, viscid flow equations with additional terms included to account for the effect of turbulence on the flow without the expense of simulating the turbulent flow structures themselves.
les	Use the Large Eddy Simulation (LES) equations.

Guidance: Choosing an equation set →

precondition

bool·default False·'precondition' only applies when solver.time settings.kind is one of unset, 'dual time stepping'

Enable low mach number preconditioning

Guidance: Choosing an equation set →

correctionincompressible only

default over_relaxed

Non-orthogonal correction method

Options

Value	What it does	When to use it
none	No non-orthogonal correction. The implicit face-normal gradient uses the full face area vector and the explicit correction is zero.	Only for meshes that are close to orthogonal.
orthogonal	Splits the face area vector $\mathbf{S}$ into an implicit part $\boldsymbol{\Delta} = \|\mathbf{S}\|\,\hat{\mathbf{d}}$ along the line between cell centres, with the remainder treated explicitly.
minimum	Takes the implicit part as the projection of $\mathbf{S}$ on the line between cell centres, $\boldsymbol{\Delta} = (\mathbf{d}\cdot\mathbf{S}/\mathbf{d}\cdot\mathbf{d})\,\mathbf{d}$ , which keeps the explicit remainder smallest.
over_relaxed default	Takes the implicit part as $\boldsymbol{\Delta} = \mathbf{d}\,\|\mathbf{S}\|^2/(\mathbf{d}\cdot\mathbf{S})$ , which grows as the mesh becomes more non-orthogonal.	The default.

Guidance: Choosing an equation set →

correction limiterincompressible only

float·default 0.5·0.0 to 1.0

Non-orthogonal correction limiter coefficient

gradient limiter typeincompressible only

default cellmd

Gradient limiter type

Options

Value	What it does
cellmd default	More robust on highly non-orthogonal meshes.
cell	Less dissipative.

gradient limiterincompressible only

float·default 0.5·0.0 to 1.0

Gradient limiter coefficient

max second order non orthogonal angleincompressible only

float·default 90·0.0 to 90.0

Maximum angle for second order non-orthogonal correction

central blendincompressible only

float·default 0.8

Central differencing blend factor

Used inatmosphere

solve energyincompressible only

bool·default False

Solve the energy (temperature) transport equation

Used inatmosphere

energy variableadvancedincompressible only

default temperature

Variable transported by the energy equation: temperature, or potential temperature theta = T (p0/p)^(R/cp) for atmospheric cases

Options

Value	What it does	When to use it
temperature default	The energy equation transports static temperature $T$ .	The default, for heat transfer without stratification.
potential temperature	Potential temperature $\theta = T (p_0/p)^{R/c_p}$ .	The natural choice for atmospheric cases.

Used inatmosphere

buoyancy diagnosticsadvancedincompressible only

bool·default False·'buoyancy diagnostics' only applies when base state is set

Log the buoyancy source against the momentum diagonal every cycle. Four host syncs per cycle: debugging only

geostrophic windadvancedincompressible only

list of float·not set by default·in m/s·'geostrophic wind' only applies when solver.fluid properties.latitude is set and non-zero

Large-scale forcing u_g: the Coriolis source becomes -f k x (u - u_g), standing in for the synoptic pressure gradient. Needs a non-zero latitude

Used inatmosphere