Standard boundary conditions

A.4 Standard boundary conditions

basic


calculated

This boundary condition is not designed to be evaluated; it is assmued that the value is assigned via field assignment, and not via a call to e.g. updateCoeffs or ȩvaluate

fixedValue

This boundary condition supplies a fixed value constraint, and is the base class for a number of other boundary conditions

fixedGradient

This boundary condition supplies a fixed gradient condition, such that the patch values are calculated using:

zeroGradient

This boundary condition applies a zero-gradient condition from the patch internal field onto the patch faces

mixed

This boundary condition provides a base class for ’mixed’ type boundary conditions, i.e. conditions that mix fixed value and patch-normal gradient conditions

directionMixed

Base class for direction-mixed boundary conditions

extrapolatedCalculated

This boundary condition applies a zero-gradient condition from the patch internal field onto the patch faces when evaluated but may also be assigned. şnGrad returns the patch gradient evaluated from the current internal and patch field values rather than returning zero

Table A.7: basic boundary conditions.

constraint


cyclic

This boundary condition enforces a cyclic condition between a pair of boundaries

cyclicACMI

This boundary condition enforces a cyclic condition between a pair of boundaries, whereby communication between the patches is performed using an arbitrarily coupled mesh interface (ACMI) interpolation

cyclicAMI

This boundary condition enforces a cyclic condition between a pair of boundaries, whereby communication between the patches is performed using an arbitrary mesh interface (AMI) interpolation

cyclicSlip

This boundary condition is a light wrapper around the cyclicFvPatchField condition, providing no new functionality

empty

This boundary condition provides an ’empty’ condition for reduced dimensions cases, i.e. 1- and 2-D geometries. Apply this condition to patches whose normal is aligned to geometric directions that do not constitue solution directions

jumpCyclic

This boundary condition provides a base class for coupled-cyclic conditions with a specified ’jump’ (or offset) between the values

jumpCyclicAMI

This boundary condition provides a base class that enforces a cyclic condition with a specified ’jump’ (or offset) between a pair of boundaries, whereby communication between the patches is performed using an arbitrary mesh interface (AMI) interpolation

nonuniformTransformCyclic

This boundary condition enforces a cyclic condition between a pair of boundaries, incorporating a non-uniform transformation

processor

This boundary condition enables processor communication across patches

processorCyclic

This boundary condition enables processor communication across cyclic patches

symmetry

This boundary condition enforces a symmetry constraint

symmetryPlane

This boundary condition enforces a symmetryPlane constraint

wedge

This boundary condition is similar to the cyclic condition, except that it is applied to 2-D geometries

Table A.8: constraint boundary conditions.

Inlet


cylindricalInletVelocity

This boundary condition describes an inlet vector boundary condition in cylindrical co-ordinates given a central axis, central point, rpm, axial and radial velocity

fanPressure

This boundary condition can be applied to assign either a pressure inlet or outlet total pressure condition for a fan

fixedFluxExtrapolatedPressure

This boundary condition sets the pressure gradient to the provided value such that the flux on the boundary is that specified by the velocity boundary condition

fixedFluxPressure

This boundary condition sets the pressure gradient to the provided value such that the flux on the boundary is that specified by the velocity boundary condition

fixedMean

This boundary condition extrapolates field to the patch using the near-cell values and adjusts the distribution to match the specified, optionally time-varying, mean value

fixedNormalInletOutletVelocity

This velocity inlet/outlet boundary condition combines a fixed normal component obtained from the ”normalVelocity” patchField supplied with a fixed or zero-gradiented tangential component

fixedPressureCompressibleDensity

This boundary condition calculates a (liquid) compressible density as a function of pressure and fluid properties:

flowRateInletVelocity

This boundary condition provides a velocity boundary condition, derived from the flux (volumetric or mass-based), whose direction is assumed to be normal to the patch

freestream

This boundary condition provides a free-stream condition. It is a ’mixed’ condition derived from the inletOutlet condition, whereby the mode of operation switches between fixed (free stream) value and zero gradient based on the sign of the flux

freestreamPressure

This boundary condition provides a free-stream condition for pressure. It is a zero-gradient condition that constrains the flux across the patch based on the free-stream velocity

mappedFlowRate

Describes a volumetric/mass flow normal vector boundary condition by its magnitude as an integral over its area

mappedVelocityFluxFixedValue

This boundary condition maps the velocity and flux from a neighbour patch to this patch

outletInlet

This boundary condition provides a generic inflow condition, with specified outflow for the case of reverse flow

outletMappedUniformInlet

This boundary conditon averages the field over the ”outlet” patch specified by name ”outletPatch” and applies this as the uniform value of the field over this patch

plenumPressure

This boundary condition provides a plenum pressure inlet condition. This condition creates a zero-dimensional model of an enclosed volume of gas upstream of the inlet. The pressure that the boundary condition exerts on the inlet boundary is dependent on the thermodynamic state of the upstream volume. The upstream plenum density and temperature are time-stepped along with the rest of the simulation, and momentum is neglected. The plenum is supplied with a user specified mass flow and temperature

pressureDirectedInletOutletVelocity

This velocity inlet/outlet boundary condition is applied to pressure boundaries where the pressure is specified. A zero-gradient condtion is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the flux with the specified inlet direction

pressureDirectedInletVelocity

This velocity inlet boundary condition is applied to patches where the pressure is specified. The inflow velocity is obtained from the flux with the specified inlet direction” direction

pressureInletOutletParSlipVelocity

This velocity inlet/outlet boundary condition for pressure boundary where the pressure is specified. A zero-gradient is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the flux with the specified inlet direction

pressureInletOutletVelocity

This velocity inlet/outlet boundary condition is applied to pressure boundaries where the pressure is specified. A zero-gradient condition is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the patch-face normal component of the internal-cell value

pressureInletUniformVelocity

This velocity inlet boundary condition is applied to patches where the pressure is specified. The uniform inflow velocity is obtained by averaging the flux over the patch, and then applying it in the direction normal to the patch faces

pressureInletVelocity

This velocity inlet boundary condition is applied to patches where the pressure is specified. The inflow velocity is obtained from the flux with a direction normal to the patch faces

pressureNormalInletOutletVelocity

This velocity inlet/outlet boundary condition is applied to patches where the pressure is specified. A zero-gradient condition is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the flux with a direction normal to the patch faces

pressurePIDControlInletVelocity

This boundary condition tries to generate an inlet velocity that maintains a specified pressure drop between two face zones downstream. The zones should fully span a duct through which all the inlet flow passes

rotatingPressureInletOutletVelocity

This velocity inlet/outlet boundary condition is applied to patches in a rotating frame where the pressure is specified. A zero-gradient is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the flux with a direction normal to the patch faces

rotatingTotalPressure

This boundary condition provides a total pressure condition for patches in a rotating frame

supersonicFreestream

This boundary condition provides a supersonic free-stream condition

surfaceNormalFixedValue

This boundary condition provides a surface-normal vector boundary condition by its magnitude

swirlFlowRateInletVelocity

This boundary condition provides a volumetric- OR mass-flow normal vector boundary condition by its magnitude as an integral over its area with a swirl component determined by the angular speed, given in revolutions per minute (RPM)

syringePressure

This boundary condition provides a pressure condition, obtained from a zero-D model of the cylinder of a syringe

timeVaryingMappedFixedValue

This boundary conditions interpolates the values from a set of supplied points in space and time. A primitive field with a separate average value

totalPressure

This boundary condition provides a total pressure condition. Four variants are possible:

totalTemperature

This boundary condition provides a total temperature condition

turbulentDFSEMInlet

Velocity boundary condition including synthesised eddies for use with LES and DES turbulent flows

turbulentInlet

This boundary condition generates a fluctuating inlet condition by adding a random component to a reference (mean) field

turbulentIntensityKineticEnergyInlet

This boundary condition provides a turbulent kinetic energy condition, based on user-supplied turbulence intensity, defined as a fraction of the mean velocity:

uniformTotalPressure

This boundary condition provides a time-varying form of the uniform total pressure boundary condition Foam::totalPressureFvPatchField

variableHeightFlowRateInletVelocity

This boundary condition provides a velocity boundary condition for multphase flow based on a user-specified volumetric flow rate

variableHeightFlowRate

This boundary condition provides a phase fraction condition based on the local flow conditions, whereby the values are constrained to lay between user-specified upper and lower bounds. The behaviour is described by:

waveSurfacePressure

This is a pressure boundary condition, whose value is calculated as the hydrostatic pressure based on a given displacement:

Table A.9: Inlet boundary conditions.

Outlet


advective

This boundary condition provides an advective outflow condition, based on solving DDt(W, field) = 0 at the boundary where W is the wave velocity and field is the field to which this boundary condition is applied

fanPressure

This boundary condition can be applied to assign either a pressure inlet or outlet total pressure condition for a fan

fixedNormalInletOutletVelocity

This velocity inlet/outlet boundary condition combines a fixed normal component obtained from the ”normalVelocity” patchField supplied with a fixed or zero-gradiented tangential component

fluxCorrectedVelocity

This boundary condition provides a velocity outlet boundary condition for patches where the pressure is specified. The outflow velocity is obtained by ”zeroGradient” and then corrected from the flux:

freestream

This boundary condition provides a free-stream condition. It is a ’mixed’ condition derived from the inletOutlet condition, whereby the mode of operation switches between fixed (free stream) value and zero gradient based on the sign of the flux

freestreamPressure

This boundary condition provides a free-stream condition for pressure. It is a zero-gradient condition that constrains the flux across the patch based on the free-stream velocity

inletOutlet

This boundary condition provides a generic outflow condition, with specified inflow for the case of return flow

inletOutletTotalTemperature

This boundary condition provides an outflow condition for total temperature for use with supersonic cases, where a user-specified value is applied in the case of reverse flow

outletPhaseMeanVelocity

This boundary condition adjusts the velocity for the given phase to achieve the specified mean thus causing the phase-fraction to adjust according to the mass flow rate

pressureDirectedInletOutletVelocity

This velocity inlet/outlet boundary condition is applied to pressure boundaries where the pressure is specified. A zero-gradient condtion is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the flux with the specified inlet direction

pressureInletOutletParSlipVelocity

This velocity inlet/outlet boundary condition for pressure boundary where the pressure is specified. A zero-gradient is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the flux with the specified inlet direction

pressureInletOutletVelocity

This velocity inlet/outlet boundary condition is applied to pressure boundaries where the pressure is specified. A zero-gradient condition is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the patch-face normal component of the internal-cell value

pressureNormalInletOutletVelocity

This velocity inlet/outlet boundary condition is applied to patches where the pressure is specified. A zero-gradient condition is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the flux with a direction normal to the patch faces

rotatingPressureInletOutletVelocity

This velocity inlet/outlet boundary condition is applied to patches in a rotating frame where the pressure is specified. A zero-gradient is applied for outflow (as defined by the flux); for inflow, the velocity is obtained from the flux with a direction normal to the patch faces

rotatingTotalPressure

This boundary condition provides a total pressure condition for patches in a rotating frame

supersonicFreestream

This boundary condition provides a supersonic free-stream condition

totalPressure

This boundary condition provides a total pressure condition. Four variants are possible:

totalTemperature

This boundary condition provides a total temperature condition

uniformInletOutlet

Variant of inletOutlet boundary condition with uniform inletValue

uniformTotalPressure

This boundary condition provides a time-varying form of the uniform total pressure boundary condition Foam::totalPressureFvPatchField

waveTransmissive

This boundary condition provides a wave transmissive outflow condition, based on solving DDt(W, field) = 0 at the boundary W is the wave velocity and field is the field to which this boundary condition is applied

Table A.10: Outlet boundary conditions.

Wall


fixedFluxExtrapolatedPressure

This boundary condition sets the pressure gradient to the provided value such that the flux on the boundary is that specified by the velocity boundary condition

fixedFluxPressure

This boundary condition sets the pressure gradient to the provided value such that the flux on the boundary is that specified by the velocity boundary condition

fixedNormalSlip

This boundary condition sets the patch-normal component to a fixed value

movingWallVelocity

This boundary condition provides a velocity condition for cases with moving walls

noSlip

This boundary condition fixes the velocity to zero at walls

partialSlip

This boundary condition provides a partial slip condition. The amount of slip is controlled by a user-supplied field

rotatingWallVelocity

This boundary condition provides a rotational velocity condition

slip

This boundary condition provides a slip constraint

translatingWallVelocity

This boundary condition provides a velocity condition for translational motion on walls

Table A.11: Wall boundary conditions.

Coupled


activeBaffleVelocity

This velocity boundary condition simulates the opening of a baffle due to local flow conditions, by merging the behaviours of wall and cyclic conditions. The baffle joins two mesh regions, where the open fraction determines the interpolation weights applied to each cyclic- and neighbour-patch contribution

activePressureForceBaffleVelocity

This boundary condition is applied to the flow velocity, to simulate the opening or closure of a baffle due to area averaged pressure or force delta, between both sides of the baffle. This is achieved by merging the behaviours of wall and cyclic baffles

fan

This boundary condition provides a jump condition, using the cyclic condition as a base

fixedJumpAMI

This boundary condition provides a jump condition, across non-conformal cyclic path-pairs, employing an arbitraryMeshInterface (AMI)

fixedJump

This boundary condition provides a jump condition, using the cyclic condition as a base

mappedField

This boundary condition provides a self-contained version of the mapped condition. It does not use information on the patch; instead it holds the data locally

mappedFixedInternalValue

This boundary condition maps the boundary and internal values of a neighbour patch field to the boundary and internal values of *this

mappedFixedPushedInternalValue

This boundary condition maps the boundary values of a neighbour patch field to the boundary and internal cell values of *this

mappedFixedValue

This boundary condition maps the value at a set of cells or patch faces back to *this

mappedFlowRate

Describes a volumetric/mass flow normal vector boundary condition by its magnitude as an integral over its area

mappedVelocityFluxFixedValue

This boundary condition maps the velocity and flux from a neighbour patch to this patch

timeVaryingMappedFixedValue

This boundary conditions interpolates the values from a set of supplied points in space and time. A primitive field with a separate average value

uniformJumpAMI

This boundary condition provides a jump condition, using the cyclicAMI condition as a base. The jump is specified as a time-varying uniform value across the patch

uniformJump

This boundary condition provides a jump condition, using the cyclic condition as a base. The jump is specified as a time-varying uniform value across the patch

Table A.12: Coupled boundary conditions.

Generic


codedFixedValue

Constructs on-the-fly a new boundary condition (derived from fixedValueFvPatchField) which is then used to evaluate

codedMixed

Constructs on-the-fly a new boundary condition (derived from mixedFvPatchField) which is then used to evaluate

fixedInternalValueFvPatchField

This boundary condition provides a mechanism to set boundary (cell) values directly into a matrix, i.e. to set a constraint condition. Default behaviour is to act as a zero gradient condition

fixedNormalSlip

This boundary condition sets the patch-normal component to a fixed value

fixedProfile

This boundary condition provides a fixed value profile condition

mappedField

This boundary condition provides a self-contained version of the mapped condition. It does not use information on the patch; instead it holds the data locally

mappedFixedInternalValue

This boundary condition maps the boundary and internal values of a neighbour patch field to the boundary and internal values of *this

mappedFixedPushedInternalValue

This boundary condition maps the boundary values of a neighbour patch field to the boundary and internal cell values of *this

mappedFixedValue

This boundary condition maps the value at a set of cells or patch faces back to *this

partialSlip

This boundary condition provides a partial slip condition. The amount of slip is controlled by a user-supplied field

phaseHydrostaticPressure

This boundary condition provides a phase-based hydrostatic pressure condition, calculated as:

prghPressure

This boundary condition provides static pressure condition for p_rgh, calculated as:

prghTotalHydrostaticPressure

This boundary condition provides static pressure condition for p_rgh, calculated as:

prghTotalPressure

This boundary condition provides static pressure condition for p_rgh, calculated as:

rotatingWallVelocity

This boundary condition provides a rotational velocity condition

slip

This boundary condition provides a slip constraint

surfaceNormalFixedValue

This boundary condition provides a surface-normal vector boundary condition by its magnitude

translatingWallVelocity

This boundary condition provides a velocity condition for translational motion on walls

uniformDensityHydrostaticPressure

This boundary condition provides a hydrostatic pressure condition, calculated as:

uniformFixedGradient

This boundary condition provides a uniform fixed gradient condition

uniformFixedValue

This boundary condition provides a uniform fixed value condition

Table A.13: Generic boundary conditions.