The
Define/Boundary Conditions... menu item opens the
Boundary Conditions panel.
Boundary Conditions Panel
The
Boundary Conditions panel allows you to set the type of a zone and display other panels to set the boundary condition parameters for each zone. See Section
here for information about using it.
Controls
Zone
contains a selectable list of zones from which you can select the zone of interest. You can check a zone type by using the mouse probe (see Section
28.3) on the displayed physical grid. This feature is particularly handy if you are setting up a problem for the first time, or if you have two or more zones of the same type and you want to determine the zone IDs. To do this you must first display the grid with the
Grid Display panel. Then click the boundary zone with the right (select) mouse button.
FLUENT will print the zone ID and type of that boundary zone in the console window.
Type
contains a selectable list of boundary condition types for the selected zone. The list contains all possible types to which the zone can be changed. When you select a boundary condition type in
Type,
Set... is automatically invoked.
Note that you cannot use this method to change zone types to or from the periodic type, since additional restrictions exist for this boundary type. Section
6.8.4 explains how to create and uncouple periodic zones.
Phase
specifies the phase for which conditions at the selected boundary
Zone are being set. This item appears if the VOF, mixture, or Eulerian multiphase model is being used. See Section
23.9.8 for details.
ID
displays the zone ID number of the selected zone. (This is for informational purposes only; you cannot edit this number.)
Set...
opens the appropriate panel for setting the boundary conditions for that particular boundary type.
Copy...
opens the
Copy BCs panel, which allows you to copy boundary conditions from one zone to other zones of the same type. See Section
7.1.5 for details.
Copy BCs Panel
The
Copy BCs panel allows you to copy boundary conditions from one zone to other zones of the same type. It is opened from the
Boundary Conditions panel. See Section
7.1.5 for details.
Controls
From Zone
specifies the zone that has the conditions you want to copy.
To Zones
specifies the zone or zones to which you want to copy the conditions.
Phase
specifies the phase for which boundary conditions are being copied. This item appears if the VOF, mixture, or Eulerian multiphase model is being used. See Section
23.9.8 for details.
Copy
copies the boundary conditions, setting all of the boundary conditions for the zones selected in the
To Zones list to be the same as the conditions for the zone selected in the
From Zone list.
Axis Panel
The
Axis panel can be used to modify the name of an axis zone; there are no conditions to be set. It is opened from the
Boundary Conditions panel. See Section
7.16 for information about axis boundaries.
Controls
Zone Name
sets the name of the zone.
Phase
displays the name of the phase. This item appears if the VOF, mixture, or Eulerian multiphase model is being used.
Exhaust Fan Panel
The
Exhaust Fan panel sets the boundary conditions for an exhaust fan zone. It is opened from the
Boundary Conditions panel. See Section
7.12.1 for details about defining the items below.
Controls
Zone Name
sets the name of the zone.
Phase
displays the name of the phase. It appears only for multiphase flows.
Momentum
contains the momentum parameters.
Gauge Pressure
sets the gauge pressure at the outlet boundary.
Backflow Direction Specification Method
sets the direction of the inflow stream should the flow reverse direction. You can choose
Direction Vector,
Normal to Boundary, or
From Neighboring Cell.
Coordinate System
contains a dropdown list for selecting the coordinate system. You can choose
Cartesian,
Cylindrical, or
Local Cylindrical. This option is available only for
Direction Vector.
X, Y, ZComponent of Flow Direction
allows you to specify the velocity components in x, y, and z directions respectively. This option is available for cartesian coordinate system.
Radial Equilibrium Pressure Distribution
enables the radial equilibrium pressure distribution. See Section
7.8.1 for details.
This item appears only for 3D and axisymmetric swirl solvers.
Pressure Jump
specifies the rise in pressure across the fan. See Section
7.12.1 for details.
Target Mass Flow Rate
allows you to set mass flow rate as a boundary condition at the outlet.
Turbulence
displays the turbulence parameters.
Specification Method
specifies which method will be used to input the turbulence parameters. You can choose
K and Epsilon (

models and RSM only),
K and Omega (

models only),
Intensity and Length Scale,
Intensity and Viscosity Ratio,
Intensity and Hydraulic Diameter, or
Turbulent Viscosity Ratio (SpalartAllmaras model only). See Section
7.2.2 for information about the inputs for each of these methods. (This item will appear only for turbulent flow calculations.)
Backflow Turbulent Kinetic Energy, Backflow Turbulent Dissipation Rate
set values for the turbulence kinetic energy
and its dissipation rate
. These items will appear if you choose
K and Epsilon as the
Specification Method.
Backflow Turbulent Kinetic Energy, Backflow Specification Dissipation Rate
set values for the turbulence kinetic energy
and its specific dissipation rate
. These items will appear if you choose
K and Omega as the
Specification Method.
Backflow Turbulence Intensity, Backflow Turbulence Length Scale
set values for turbulence intensity
and turbulence length scale
. These items will appear if you choose
Intensity and Length Scale as the
Specification Method.
Backflow Turbulence Intensity, Backflow Turbulent Viscosity Ratio
set values for turbulence intensity
and turbulent viscosity ratio
. These items will appear if you choose
Intensity and Viscosity Ratio as the
Specification Method.
Backflow Turbulence Intensity, Backflow Hydraulic Diameter
set values for turbulence intensity
and hydraulic diameter
. These items will appear if you choose
Intensity and Hydraulic Diameter as the
Specification Method.
Backflow Turbulent Viscosity Ratio
sets the value of the backflow turbulent viscosity ratio
. This item will appear if you choose
Turbulent Viscosity Ratio as the
Specification Method.
ReynoldsStress Specification Method
specifies which method will be used to determine the backflow Reynolds stress boundary conditions when the Reynolds stress turbulence model is used. You can choose either
K or Turbulence Intensity or
ReynoldsStress Components. If you choose the former,
FLUENT will compute the Reynolds stresses for you. If you choose the latter, you will explicitly specify the Reynolds stresses yourself. See Section
12.20.3 for details. (This item will appear only for RSM turbulent flow calculations.)
Backflow UU,VV,WW,UV,VW,UW Reynolds Stresses
specify the backflow Reynolds stress components when
ReynoldsStress Components is chosen as the
ReynoldsStress Specification Method.
Thermal
contains the thermal parameters. This parameter is available only when the energy equation is turned on.
Backflow Total Temperature
sets the total temperature of the inflow stream should the flow reverse direction.
Radiation
contains the boundary conditions for the radiation model at the exhaust fan.
Participates in S2S Radiation
specifies whether or not fan participate in S2S radiation. This parameter is available only if you select
Surface to Surface radiation model.
Participates in Solar Ray Tracing
specifies whether or not fan participate in solar ray tracing.
External Black Body Temperature Method, Internal Emissivity
set the radiation boundary conditions when you are using the P1 model, the DTRM, the discrete ordinates model, or the S2S model for radiation heat transfer. See Section
13.3.15 for details.
Species
contains the species parameters.
Mean Mixture Fraction, Mixture Fraction Variance
set inlet values for the PDF mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model.)
Secondary Mean Mixture Fraction, Secondary Mixture Fraction Variance
set inlet values for the secondary mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model with two mixture fractions.)
Species Mass Fractions
contains inputs for the mass fractions of defined species. See Section
14.1.5 for details about these inputs. These items will appear only if you are modeling nonreacting multispecies flow or you are using the finiterate reaction formulation.
Backflow Progress Variable
sets the value of the progress variable for premixed turbulent combustion. See Section
16.3.5 for details.
This item will appear only if the premixed or partially premixed combustion model is used.
DPM
contains the discrete phase parameters. This tab is available only if you have defined atleast one injection.
Discrete Phase BC Type
sets the way that the discrete phase behaves with respect to the boundary. This item appears when one or more injections have been defined.
reflect
rebounds the particle off the boundary with a change in its momentum as defined by the coefficient of restitution. (See Figure
22.13.1.)
trap
terminates the trajectory calculations and records the fate of the particle as "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure
22.13.2.
escape
reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure
22.13.3.
walljet
indicates that the direction and velocity of the droplet particles are given by the resulting momentum flux, which is a function of the impingement angle. See Figure
22.13.4.
wallfilm
consists of four regimes: stick, rebound, spread, and splash, which are based on the impact energy and wall temperature. Detailed information on the wallfilm model can be found in Section
22.4. The
Number Of Splashed Drops must be specified.
userdefined
specifies a userdefined function to define the discrete phase boundary condition type.
Discrete Phase BC Function
sets the userdefined function from the dropdown list.
Multiphase
contains the multiphase parameters.
Backflow Granular Temperature
specifies temperature for the solids phase and is proportional to the kinetic energy of the random motion of the particles.
Backflow Volume Fraction
specifies the volume fraction of the secondary phase selected in the
Boundary Conditions panel. This section of the panel will appear when one of the multiphase models is being used. See Section
23.9.8 for details.
UDS
contains the UDS parameters.
UserDefined Scalar Boundary Condition
appears only if user defines scalars are specified.
User Scalarn
specifies the whether the scalar is a specified flux or a specified value.
UserDefined Scalar Boundary Value
appears only if user defines scalars are specified.
User Scalarn
specifies the value of the scalar.
Fan Panel
The
Fan panel sets the boundary conditions for a fan zone. It is opened from the
Boundary Conditions panel. See Section
7.20.2 for details about the items below.
Controls
Zone Name
sets the name of the zone.
PressureJump Specification
contains inputs that define the pressure jump across the fan.
Reverse Fan Direction
sets the fan flow direction relative to the zone direction. If
Zone Average Direction is pointing in the direction you want the fan to blow, do
not select
Reverse Flow; if it is pointing in the opposite direction, select
Reverse Flow.
Zone Average Direction
displays the (faceaveraged) direction vector for the zone as an aid in determining whether or not you want to select
Reverse Flow.
Profile Specification of PressureJump
enables the use of a boundary profile or userdefined function for the pressure jump specification. See Section
7.26 or the separate
UDF Manual for details. When this option is enabled,
Pressure Jump Profile will appear in the panel and the next four items below it will not.
Pressure Jump Profile
contains a dropdown list from which you can select a boundary profile or a userdefined function for the pressure jump definition. This item will appear if you enable
Profile Specification of PressureJump.
PressureJump
specifies the pressurejump as a constant value or as a polynomial, piecewiselinear, or piecewisepolynomial function of velocity. See Section
7.20.2 for details.
Limit Polynomial Velocity Range
limits the minimum and maximum velocity magnitudes used to calculate the pressure jump when it is defined as a function of velocity.
Min Velocity Magnitude, Max Velocity Magnitude
specify the minimum and maximum values to which the velocity magnitude is limited (when the
Limit Polynomial Velocity Range option is enabled).
Calculate PressureJump from Average Conditions
enables the option to use the massaveraged velocity normal to the fan to determine a single pressurejump value for all faces in the fan zone.
Discrete Phase BC Type
sets the way that the discrete phase behaves with respect to the boundary. This item appears when one or more injections have been defined.
reflect
rebounds the particle off the boundary with a change in its momentum as defined by the coefficient of restitution. (See Figure
22.13.1.)
trap
terminates the trajectory calculations and records the fate of the particle a s "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure
22.13.2.
escape
reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure
22.13.3.
walljet
indicates that the direction and velocity of the droplet particles are given by the resulting momentum flux, which is a function of the impingement angle. See Figure
22.13.4.
wallfilm
consists of four regimes: stick, rebound, spread, and splash, which are based on the impact energy and wall temperature. Detailed information on the wallfilm model can be found in Section
22.4. The
Number Of Splashed Drops must be specified.
userdefined
specifies a userdefined function to define the discrete phase boundary condition type.
Discrete Phase BC Function
sets the userdefined function from the dropdown list.
SwirlVelocity Specification
contains inputs for the specification of fan swirl velocity. This section of the panel appears only for 3D models.
SwirlVelocity Specification
enables the specification of a swirl velocity for the fan.
Fan Axis
sets the direction vector for the fan's axis of rotation.
Fan Origin
sets the origin in the global coordinate system through which the fan rotation axis passes.
Fan Hub Radius
set the radius of the hub. The default is 1e6 to avoid division by zero in the polynomial.
Profile Specification of Tangential Velocity
enables the use of a boundary profile or userdefined function for the tangential velocity specification. See Section
7.26 or the separate
UDF Manual for details. When this option is enabled,
Tangential Velocity Profile will appear in the panel and
TangentialVelocity Polynomial Coefficients will not.
Tangential Velocity Profile
contains a dropdown list from which you can select a boundary profile or a userdefined function for the definition of the tangential velocity. This item will appear if you enable
Profile Specification of Tangential Velocity.
TangentialVelocity Polynomial Coefficients
sets the coefficients for the tangential velocity polynomial. Separate the coefficients by spaces.
Profile Specification of Radial Velocity
enables the use of a boundary profile or userdefined function for the radial velocity specification. See Section
7.26 or the separate
UDF Manual for details. When this option is enabled,
Radial Velocity Profile will appear in the panel and
RadialVelocity Polynomial Coefficients will not.
Radial Velocity Profile
contains a dropdown list from which you can select a boundary profile or a userdefined function for the definition of the radial velocity. This item will appear if you enable
Profile Specification of Radial Velocity.
RadialVelocity Polynomial Coefficients
sets the coefficients for the radial velocity polynomial. Separate the coefficients by spaces.
Fluid Panel
The
Fluid panel sets the conditions for a fluid cell zone. It is opened from the
Boundary Conditions panel. See Sections
7.17.1 and
7.19.6 for details about the items below.
Controls
Zone Name
sets the name of the zone.
Material Name
sets the fluid material. The dropdown list contains the names of all materials that have been loaded into the solver. Materials are defined with the
Materials panel.
If you are modeling species transport or multiphase flow, the
Material Name list will not appear in the
Fluid panel. For species calculations, the mixture material for all fluid zones will be the material you specified in the
Species Model panel. For multiphase flows, the materials are specified when you define the phases, as described in Section
23.10.3.
Porous Zone
indicates that the zone is a porous medium. Additional items will appear in the panel when this option is enabled. See Section
7.19.6 for details.
Laminar Zone
disables the calculation of turbulence production
in the fluid zone (appears only for turbulent flow calculations using the SpalartAllmaras model or one of the

or

models). See Section
7.17.1 for details.
Source Terms
enables the specification of volumetric sources of mass, momentum, energy, etc. When you turn on this option, the
Source Terms tab will be enabled to allow you to input the values for the desired sources. See Section
7.28 for details.
Fixed Values
enables the fixing of the value of one or more variables in the fluid zone, rather than computing them during the calculation. See Section
7.27 for details.
You can fix values for velocity components, temperature, and species mass fractions only if you are using the pressurebased solver.
Participates In Radiation
specifies whether or not the fluid zone participates in radiation. This option appears when you are using the DO model for radiation.
Reaction
enables/disables reactions in the porous zone.
Motion
lists the parameters associated to the fluid motion.
RotationAxis Origin
specifies the origin for the fluid zone's axis of rotation. See Section
7.17.1 for details. This item will appear only for 3D and 2D nonaxisymmetric models.
RotationAxis Direction
specifies the direction vector for the fluid zone's axis of rotation. See Section
7.17.1 for details. This item will appear only for 3D.
Motion Type
specifies zone motion for a rotating or translating reference frame or for a sliding zone in a sliding mesh problem. The default selection of
Stationary indicates that the zone is not moving. To define the motion of a moving reference frame for the zone, select
Moving Reference Frame and specify the items below in the expanded portion of the panel. See Section
10.7,
10.10.1, or
10.10.2 for details. To define zone motion for a moving (sliding) mesh, select
Moving Mesh and set the appropriate parameters below. See Section
11.4.2 for details.
Rotational Velocity
contains an input field for the rotational
Speed of the zone. This item will appear if you select
Moving Reference Frame or
Moving Mesh in the
Motion Type list.
Translational Velocity
contains inputs for the
X,
Y, and
Z velocities of the zone. This item will appear if you select
Moving Reference Frame or
Moving Mesh in the
Motion Type list.
Porous Zone
lists the parameters associated to porous zone.
Conical
enables the specification of a conical (or cylindrical) porous medium. This item will appear only when the
Porous Zone option is enabled for a 3D case.
Cone Half Angle
specifies the angle between the cone's axis and its surface (see Figure
7.19.2). Set this to 0 to define the porous region using a cylindrical coordinate system. This item will appear only when the
Porous Zone and
Conical options are enabled.
Snap to Zone
aligns the plane (or line, in 2D) tool with the zone selected in the dropdown list. The tool is centered at the centroid of the zone, with the tool's axis normal to the zone. If this axis is not the desired cone axis, reposition the tool (as described in Section
27.6.1). When you are satisfied with the axis, click on the
Update From Plane Tool (or
Update From Line Tool) button to update the
Cone Axis Vector fields.
This item will appear only when the
Porous Zone and
Conical options are enabled.
Update From Plane Tool
(
Update From Line Tool in 2D) updates the
Direction1 Vector and (in 3D) the
Direction2 Vector from the plane tool orientation. If the
Conical option is enabled, this button will update the
Cone Axis Vector and the
Point on Cone Axis. See Section
7.19.6 for details. This item will appear only when the
Porous Zone option is enabled.
Direction1 Vector, Direction2 Vector
indicate the directions for which the resistance coefficients are defined. See Section
7.19.6 for details. These items will appear only when the
Porous Zone option is enabled, but the
Conical option is not. (In 2D, only
Direction1 Vector will appear.)
Cone Axis Vector
specifies the
X,Y,Z vector for the cone's axis.
This item will appear only when the
Porous Zone and
Conical options are enabled.
Point on Cone Axis
specifies a point on the cone's axis. This point will be used by
FLUENT to transform the resistances to the Cartesian coordinate system.
This item will appear only when the
Porous Zone and
Conical options are enabled.
Viscous Resistance, Inertial Resistance
contain inputs for the viscous resistance coefficient
and the inertial resistance coefficient
in each direction. See Section
7.19.6 for details. These items will appear only when the
Porous Zone option is enabled.
If you have enabled the
Conical option,
Direction1 is the cone axis direction,
Direction2 is the normal to the cone surface (radial (
) direction for a cylinder), and
Direction3 is the circumferential (
) direction.
Power Law Model
contains inputs for the
C0 and
C1 coefficients in the power law model for porous media. See Section
7.19.6 for details.
Fluid Porosity
contains additional inputs for the porous medium. See Section
7.19.6 for details.
Porosity
sets the volume fraction of fluid within the porous region.
Solid Material Name
specifies the solid material in the porous region.
Reaction
lists the parameters for reactions in the porous zone.
Reaction Mechanism
allows you to specify a defined group, or mechanism, of available reactions. See Section
14.1.4 for details about defining reaction mechanisms.
SurfacetoVolume Ratio
specifies the surface area of the pore walls per unit volume (
), and can be thought of as a measure of catalyst loading. With this value,
FLUENT can calculate the total surface area on which the reaction takes place in each cell by multiplying
by the volume of the cell.
Fixed Values
lists the fixed parameters of the fluid zone.
Local Coordinate System For Fixed Velocities
enables the specification of fixed cylindrical velocity components instead of Cartesian components. The local coordinate system is defined by the
RotationAxis Origin and
RotationAxis Direction.
This item is available only in 3D, and only when the
Fixed Values option is on.
Inlet Vent Panel
The
Inlet Vent panel sets the boundary conditions for an inlet vent zone. It is opened from the
Boundary Conditions panel. See Section
7.6.1 for details about defining the items below.
Controls
Zone Name
sets the name of the zone.
Momentum
contains the momentum parameters.
Gauge Total Pressure
sets the gauge total (or stagnation) pressure of the inflow stream. If you are using moving reference frames, see Section
7.3.1 for information about relative and absolute total pressure.
Supersonic/Initial Gauge Pressure
sets the static pressure on the boundary when the flow becomes (locally) supersonic. It is also used to compute initial values for pressure, temperature, and velocity if the inlet vent boundary condition is selected for computing initial values (see Section
25.14.1).
Direction Specification Method
specifies the method you will use to define the flow direction. If you choose
Direction Vector, you will define the flow direction components, and if you choose
Normal to Boundary no inputs are required. See Section
7.3.1 for information on specifying flow direction.
Coordinate System
specifies whether
Cartesian,
Cylindrical, or
Local Cylindrical vector components will be input. This item will appear only for 3D cases in which you have selected
Direction Vector as the
Direction Specification Method.
X,Y,ZComponent of Flow Direction
set the direction of the flow at the inlet boundary. These items will appear if the selected
Coordinate System is
Cartesian or the model is 2D nonaxisymmetric.
Radial, Tangential, Axial Component of Flow Direction
set the direction of the flow at the inlet boundary. These items will appear for 2D axisymmetric cases, or for 3D cases for which the selected
Coordinate System is
Cylindrical or
Local Cylindrical.
X,Y,ZComponent of Axis Direction
sets the direction of the axis. These items will appear if the selected
Coordinate System is
Local Cylindrical.
X,Y,ZCoordinate of Axis Origin
sets the location of the axis origin. These items will appear if the selected
Coordinate System is
Local Cylindrical.
LossCoefficient
sets the nondimensional loss coefficient used to compute the pressure drop. See Section
7.6.1 for details.
Tubulence
lists the turbulence parameters.
Specification Method
specifies which method will be used to input the turbulence parameters. You can choose
K and Epsilon (

models and RSM only),
K and Omega (

models only),
Intensity and Length Scale,
Intensity and Viscosity Ratio,
Intensity and Hydraulic Diameter, or
Turbulent Viscosity Ratio (SpalartAllmaras model only). See Section
7.2.2 for information about the inputs for each of these methods. (This item will appear only for turbulent flow calculations.)
Turbulent Kinetic Energy, Turbulent Dissipation Rate
set values for the turbulence kinetic energy
and its dissipation rate
. These items will appear if you choose
K and Epsilon as the
Specification Method.
Turbulent Kinetic Energy, Specific Dissipation Rate
set values for the turbulence kinetic energy
and its specific dissipation rate
. These items will appear if you choose
K and Omega as the
Specification Method.
Turbulence Intensity, Turbulence Length Scale
set values for turbulence intensity
and turbulence length scale
. These items will appear if you choose
Intensity and Length Scale as the
Specification Method.
Turbulence Intensity, Turbulent Viscosity Ratio
set values for turbulence intensity
and turbulent viscosity ratio
. These items will appear if you choose
Intensity and Viscosity Ratio as the
Specification Method.
Turbulence Intensity, Hydraulic Diameter
set values for turbulence intensity
and hydraulic diameter
. These items will appear if you choose
Intensity and Hydraulic Diameter as the
Specification Method.
Turbulent Viscosity Ratio
sets the value of the turbulent viscosity ratio
. This item will appear if you choose
Turbulent Viscosity Ratio as the
Specification Method.
ReynoldsStress Specification Method
specifies which method will be used to determine the Reynolds stress boundary conditions when the Reynolds stress turbulence model is used. You can choose either
K or Turbulence Intensity or
ReynoldsStress Components. If you choose the former,
FLUENT will compute the Reynolds stresses for you. If you choose the latter, you will explicitly specify the Reynolds stresses yourself. See Section
12.20.3 for details. (This item will appear only for RSM turbulent flow calculations.)
UU,VV,WW,UV,VW,UW Reynolds Stresses
specify the Reynolds stress components when
ReynoldsStress Components is chosen as the
ReynoldsStress Specification Method.
Thermal
contains the thermal parameters.
Total Temperature
sets the total temperature of the inflow stream. If you are using moving reference frames, see Section
7.3.1 for information about relative and absolute total temperature.
Radiation
contains the radiation parameters.
Participates in Solar Ray Tracing
specifies whether or not inlet vent participate in solar ray tracing.
External Black Body Temperature Method, Internal Emissivity
set the radiation boundary conditions when you are using the P1 model, the DTRM, the discrete ordinates model, or the S2S model for radiation heat transfer. See Section
13.3.15 for details.
Species
contains the species parameters.
Species Mass Fractions
contains inputs for the mass fractions of defined species. See Section
14.1.5 for details about these inputs. (These items will appear only if you are modeling nonreacting multispecies flow or you are using the finiterate reaction formulation.)
Mean Mixture Fraction, Mixture Fraction Variance
set inlet values for the PDF mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model.)
Secondary Mean Mixture Fraction, Secondary Mixture Fraction Variance
set inlet values for the secondary mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model with two mixture fractions.)
Progress Variable
sets the value of the progress variable for premixed turbulent combustion. See Section
16.3.5 for details.
This item will appear only if the premixed or partially premixed combustion model is used.
DPM
contains the discrete phase parameters.
Discrete Phase BC Type
sets the way that the discrete phase behaves with respect to the boundary. This item appears when one or more injections have been defined.
reflect
rebounds the particle off the boundary with a change in its momentum as defined by the coefficient of restitution. (See Figure
22.13.1.)
trap
terminates the trajectory calculations and records the fate of the particle as "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure
22.13.2.
escape
reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure
22.13.3.
walljet
indicates that the direction and velocity of the droplet particles are given by the resulting momentum flux, which is a function of the impingement angle. See Figure
22.13.4.
wallfilm
consists of four regimes: stick, rebound, spread, and splash, which are based on the impact energy and wall temperature. Detailed information on the wallfilm model can be found in Section
22.4. The
Number Of Splashed Drops must be specified.
userdefined
specifies a userdefined function to define the discrete phase boundary condition type.
Discrete Phase BC Function
sets the userdefined function from the dropdown list.
Multiphase
contains the multiphase parameters.
Granular Temperature
specifies temperature for the solids phase and is proportional to the kinetic energy of the random motion of the particles.
Volume Fraction
specifies the volume fraction of the secondary phase selected in the
Boundary Conditions panel. This section of the panel will appear when one of the multiphase models is being used. See Section
23.9.8 for details.
UDS
contains the UDS parameters.
UserDefined Scalar Boundary Condition
appears only if user defines scalars are specified.
User Scalarn
specifies the whether the scalar is a specified flux or a specified value.
UserDefined Scalar Boundary Value
appears only if user defines scalars are specified.
User Scalarn
specifies the value of the scalar.
Intake Fan Panel
The
Intake Fan panel sets the boundary conditions for an intake fan zone. It is opened from the
Boundary Conditions panel. See Section
7.7.1 for details about defining the items below.
Controls
Zone Name
sets the name of the zone.
Momentum
contains the momentum parameters.
Gauge Total Pressure
sets the gauge total (or stagnation) pressure of the inflow stream. If you are using moving reference frames, see Section
7.3.1 for information about relative and absolute total pressure.
Supersonic/Initial Gauge Pressure
sets the static pressure on the boundary when the flow becomes (locally) supersonic. It is also used to compute initial values for pressure, temperature, and velocity if the intake fan boundary condition is selected for computing initial values (see Section
25.14.1).
Direction Specification Method
specifies the method you will use to define the flow direction. If you choose
Direction Vector, you will define the flow direction components, and if you choose
Normal to Boundary no inputs are required. See Section
7.3.1 for information on specifying flow direction.
Coordinate System
specifies whether
Cartesian,
Cylindrical, or
Local Cylindrical vector components will be input. This item will appear only for 3D cases in which you have selected
Direction Vector as the
Direction Specification Method.
X,Y,ZComponent of Flow Direction
set the direction of the flow at the inlet boundary. For compressible flow, if the inflow becomes supersonic, the velocity is not reoriented. These items will appear if the selected
Coordinate System is
Cartesian or the model is 2D nonaxisymmetric.
Radial, Tangential, Axial Component of Flow Direction
set the direction of the flow at the inlet boundary. For compressible flow, if the inflow becomes supersonic, the velocity is not reoriented. These items will appear for 2D axisymmetric cases, or for 3D cases for which the selected
Coordinate System is
Cylindrical or
Local Cylindrical.
X,Y,ZComponent of Axis Direction
sets the direction of the axis. These items will appear if the selected
Coordinate System is
Local Cylindrical.
X,Y,ZCoordinate of Axis Origin
sets the location of the axis origin. These items will appear if the selected
Coordinate System is
Local Cylindrical.
PressureJump
specifies the rise in pressure across the fan. See Section
7.7.1 for details.
Turbulence
consists of the turbulence parameters.
Specification Method
specifies which method will be used to input the turbulence parameters. You can choose
K and Epsilon (

models and RSM only),
K and Omega (

models only),
Intensity and Length Scale,
Intensity and Viscosity Ratio,
Intensity and Hydraulic Diameter, or
Turbulent Viscosity Ratio (SpalartAllmaras model only). See Section
7.2.2 for information about the inputs for each of these methods. (This item will appear only for turbulent flow calculations.)
Turbulence Kinetic Energy, Turbulence Dissipation Rate
set values for the turbulence kinetic energy
and its dissipation rate
. These items will appear if you choose
K and Epsilon as the
Specification Method.
Turbulence Kinetic Energy, Specific Dissipation Rate
set values for the turbulence kinetic energy
and its specific dissipation rate
. These items will appear if you choose
K and Omega as the
Specification Method.
Turbulence Intensity, Turbulence Length Scale
set values for turbulence intensity
and turbulence length scale
. These items will appear if you choose
Intensity and Length Scale as the
Specification Method.
Turbulence Intensity, Turbulent Viscosity Ratio
set values for turbulence intensity
and turbulent viscosity ratio
. These items will appear if you choose
Intensity and Viscosity Ratio as the
Specification Method.
Turbulence Intensity, Hydraulic Diameter
set values for turbulence intensity
and hydraulic diameter
. These items will appear if you choose
Intensity and Hydraulic Diameter as the
Specification Method.
Turbulent Viscosity Ratio
sets the value of the turbulent viscosity ratio
. This item will appear if you choose
Turbulent Viscosity Ratio as the
Specification Method.
ReynoldsStress Specification Method
specifies which method will be used to determine the Reynolds stress boundary conditions when the Reynolds stress turbulence model is used. You can choose either
K or Turbulence Intensity or
ReynoldsStress Components. If you choose the former,
FLUENT will compute the Reynolds stresses for you. If you choose the latter, you will explicitly specify the Reynolds stresses yourself. See Section
12.20.3 for details. (This item will appear only for RSM turbulent flow calculations.)
UU,VV,WW,UV,VW,UW Reynolds Stresses
specify the Reynolds stress components when
ReynoldsStress Components is chosen as the
ReynoldsStress Specification Method.
Thermal
contains the thermal parameters.
Total Temperature
sets the total temperature of the inflow stream. If you are using moving reference frames, see Section
7.3.1 for information about relative and absolute total temperature.
Radiation
contains the radiation parameters.
Participates in Solar Ray Tracing
specifies whether or not intakefan participate in solar ray tracing.
External Black Body Temperature Method, Internal Emissivity
set the radiation boundary conditions when you are using the P1 model, the DTRM, the discrete ordinates model, or the S2S model for radiation heat transfer. See Section
13.3.15 for details.
Species
contains the species parameters.
Species Mass Fractions
contains inputs for the mass fractions of defined species. See Section
14.1.5 for details about these inputs. (These items will appear only if you are modeling nonreacting multispecies flow or you are using the finiterate reaction formulation.)
Mean Mixture Fraction, Mixture Fraction Variance
set inlet values for the PDF mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model.)
Secondary Mean Mixture Fraction, Secondary Mixture Fraction Variance
set inlet values for the secondary mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model with two mixture fractions.)
Progress Variable
sets the value of the progress variable for premixed turbulent combustion. See Section
16.3.5 for details.
This item will appear only if the premixed or partially premixed combustion model is used.
DPM
contains the discrete phase parameters.
Discrete Phase BC Type
sets the way that the discrete phase behaves with respect to the boundary. This item appears when one or more injections have been defined.
reflect
rebounds the particle off the boundary with a change in its momentum as defined by the coefficient of restitution. (See Figure
22.13.1.)
trap
terminates the trajectory calculations and records the fate of the particle as "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure
22.13.2.
escape
reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure
22.13.3.
walljet
indicates that the direction and velocity of the droplet particles are given by the resulting momentum flux, which is a function of the impingement angle. See Figure
22.13.4.
wallfilm
consists of four regimes: stick, rebound, spread, and splash, which are based on the impact energy and wall temperature. Detailed information on the wallfilm model can be found in Section
22.4. The
Number Of Splashed Drops must be specified.
userdefined
specifies a userdefined function to define the discrete phase boundary condition type.
Discrete Phase BC Function
sets the userdefined function from the dropdown list.
Multiphase
contains the multiphase parameters.
Granular Temperature
specifies temperature for the solids phase and is proportional to the kinetic energy of the random motion of the particles.
Volume Fraction
specifies the volume fraction of the secondary phase selected in the
Boundary Conditions panel. This section of the panel will appear when one of the multiphase models is being used. See Section
23.9.8 for details.
UDS
contains the UDS parameters.
UserDefined Scalar Boundary Condition
appears only if user defines scalars are specified.
User Scalarn
specifies the whether the scalar is a specified flux or a specified value.
UserDefined Scalar Boundary Value
appears only if user defines scalars are specified.
User Scalarn
specifies the value of the scalar.
interface Panel
The
interface panel can be used to modify the name of an interface zone; there are no conditions to be set. It is opened from the
Boundary Conditions panel. Interface zones are used for multiple reference frame and sliding mesh calculations, and for nonconformal grids. See Section
10.3.1,
11.2, and
6.4 for details.
Controls
Zone Name
sets the name of the zone.
Phase
displays the name of the phase. This item appears only for multiphase flows.
interior Panel
The
interior panel can be used to modify the name of an interior zone; there are no conditions to be set. It is opened from the
Boundary Conditions panel.
Controls
Zone Name
sets the name of the zone.
Phase
displays the name of the phase. This item appears only for multiphase flows.
MassFlow Inlet Panel
The
MassFlow Inlet panel sets the boundary conditions for a massflow inlet zone. It is opened from the
Boundary Conditions panel. See Section
7.5.1 for details about defining the items below.
Controls
Zone Name
sets the name of the zone.
Momentum
displays the momentum boundary conditions.
Mass Flow Specification Method
specifies whether you are defining
Mass Flow Rate,
Mass Flux, or
Mass Flux with Average Mass Flux.
Mass FlowRate
sets the prescribed mass flow rate for the zone. This flow rate is converted internally to a prescribed uniform mass flux over the zone by dividing the flow rate by the flow direction area projection of the zone. This item will appear if you selected
Mass Flow Rate in the
Mass Flow Specification Method list.
Note that for axisymmetric problems, this mass flow rate is the flow rate through the entire (
radian) domain, not through a 1radian slice.
Mass Flux
sets the prescribed mass flux for the zone. This item will appear if you selected
Mass Flux or
Mass Flux with Average Mass Flux in the
Mass Flow Specification Method list.
Note that for axisymmetric problems, this mass flux is the flux through a 1radian slice of the domain.
Average Mass Flux
sets the average mass flux through the zone. See Section
7.5.1 for details. This item will appear if you selected
Mass Flux with Average Mass Flux in the
Mass Flow Specification Method list.
Note that for axisymmetric problems, this mass flux is the flux through a 1radian slice of the domain.
Supersonic/Initialization Gauge Pressure
sets the static pressure that will be used to initialize the flow field if the mass flow inlet boundary condition is selected for initializing flow properties (see Section
25.14.1).
Direction Specification Method
specifies the method you will use to define the flow direction. If you choose
Direction Vector, you will define the flow direction components, and if you choose
Normal to Boundary no inputs are required. See Section
7.3.1 for information on specifying flow direction.
Reference Frame
specifies the reference frame for the mass flow. If the cell zone adjacent to the massflow inlet is moving, you can choose to specify relative or absolute velocities by selecting
Relative to Adjacent Cell Zone or
Absolute in the
Reference Frame dropdown list.
Coordinate System
specifies whether
Cartesian,
Cylindrical, or
Local Cylindrical vector components will be input. This item will appear only for 3D cases in which you have selected
Direction Vector as the
Direction Specification Method.
X,Y,ZComponent of FlowDirection
set the velocitydirection vector of the inflow stream. This vector does not need to be normalized (e.g., you can specify the vector (1 1 1) rather than (0.577 0.577 0.577)). These items will appear if the selected
Coordinate System is
Cartesian or the model is 2D nonaxisymmetric.
Radial, Tangential, Axial Component of Flow Direction
set the velocitydirection vector of the inflow stream. These items will appear for 2D axisymmetric cases, or for 3D cases for which the selected
Coordinate System is
Cylindrical or
Local Cylindrical.
Turbulence
contains the turbulence parameters.
Specification Method
specifies which method will be used to input the turbulence parameters. You can choose
K and Epsilon (

models and RSM only),
K and Omega (

models only),
Intensity and Length Scale,
Intensity and Viscosity Ratio,
Intensity and Hydraulic Diameter, or
Turbulent Viscosity Ratio (SpalartAllmaras model only). See Section
7.2.2 for information about the inputs for each of these methods. (This item will appear only for turbulent flow calculations.)
Turbulence Kinetic Energy, Turbulence Dissipation Rate
set values for the turbulence kinetic energy
and its dissipation rate
. These items will appear if you choose
K and Epsilon as the
Specification Method.
Turbulence Kinetic Energy, Specific Dissipation Rate
set values for the turbulence kinetic energy
and its specific dissipation rate
. These items will appear if you choose
K and Omega as the
Specification Method.
Turbulence Intensity, Turbulence Length Scale
set values for turbulence intensity
and turbulence length scale
. These items will appear if you choose
Intensity and Length Scale as the
Specification Method.
Turbulence Intensity, Turbulent Viscosity Ratio
set values for turbulence intensity
and turbulent viscosity ratio
. These items will appear if you choose
Intensity and Viscosity Ratio as the
Specification Method.
Turbulence Intensity, Hydraulic Diameter
set values for turbulence intensity
and hydraulic diameter
. These items will appear if you choose
Intensity and Hydraulic Diameter as the
Specification Method.
Turbulent Viscosity Ratio
sets the value of the turbulent viscosity ratio
. This item will appear if you choose
Turbulent Viscosity Ratio as the
Specification Method.
ReynoldsStress Specification Method
specifies which method will be used to determine the Reynolds stress boundary conditions when the Reynolds stress turbulence model is used. You can choose either
K or Turbulence Intensity or
ReynoldsStress Components. If you choose the former,
FLUENT will compute the Reynolds stresses for you. If you choose the latter, you will explicitly specify the Reynolds stresses yourself. See Section
12.20.3 for details. (This item will appear only for RSM turbulent flow calculations.)
UU,VV,WW,UV,VW,UW Reynolds Stresses
specify the Reynolds stress components when
ReynoldsStress Components is chosen as the
ReynoldsStress Specification Method.
Thermal
contains the thermal parameters.
Total Temperature
sets the total temperature of the inflow stream.
Radiation
contains the radiation parameters.
Participates in Solar Ray Tracing
specifies whether or not massflow inlet participate in solar ray tracing.
External Black Body Temperature Method, Internal Emissivity
set the radiation boundary conditions when you are using the P1 model, the DTRM, the discrete ordinates model, or the S2S model for radiation heat transfer. See Section
13.3.15 for details.
Species
contains the species parameters.
Species Mass Fractions
contains inputs for the mass fractions of defined species. See Section
14.1.5 for details about these inputs. These items will appear only if you are modeling nonreacting multispecies flow or you are using the finiterate reaction formulation.
Progress Variable
sets the value of the progress variable for premixed turbulent combustion. See Section
16.3.5 for details.
This item will appear only if the premixed or partially premixed combustion model is used.
Mean Mixture Fraction, Mixture Fraction Variance
set inlet values for the PDF mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model.)
Secondary Mean Mixture Fraction, Secondary Mixture Fraction Variance
set inlet values for the secondary mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model with two mixture fractions.)
DPM
contains the discrete phase parameters.
Discrete Phase BC Type
sets the way that the discrete phase behaves with respect to the boundary. This item appears when one or more injections have been defined.
reflect
rebounds the particle off the boundary with a change in its momentum as defined by the coefficient of restitution. (See Figure
22.13.1.)
trap
terminates the trajectory calculations and records the fate of the particle as "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure
22.13.2.
escape
reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure
22.13.3.
walljet
indicates that the direction and velocity of the droplet particles are given by the resulting momentum flux, which is a function of the impingement angle. See Figure
22.13.4.
wallfilm
consists of four regimes: stick, rebound, spread, and splash, which are based on the impact energy and wall temperature. Detailed information on the wallfilm model can be found in Section
22.4. The
Number Of Splashed Drops must be specified.
userdefined
specifies a userdefined function to define the discrete phase boundary condition type.
Discrete Phase BC Function
sets the userdefined function from the dropdown list.
UDS
contains the UDS parameters.
UserDefined Scalar Boundary Condition
appears only if user defines scalars are specified.
User Scalarn
specifies the whether the scalar is a specified flux or a specified value.
UserDefined Scalar Boundary Value
appears only if user defines scalars are specified.
User Scalarn
specifies the value of the scalar.
Outflow Panel
The
Outflow panel sets the boundary conditions for an outflow zone. It is opened from the
Boundary Conditions panel. See Section
7.10.2 for details about using outflow boundaries.
Controls
Zone Name
sets the name of the zone.
Flow Rate Weighting
specifies the portion of the outflow that is going through the boundary. See Section
7.10.3 for details.
External Black Body Temperature Method, Internal Emissivity
set the radiation boundary conditions when you are using the P1 model, the DTRM, the discrete ordinates model, or the S2S model for radiation heat transfer. See Section
13.3.15 for details.
Discrete Phase BC Type
sets the way that the discrete phase behaves with respect to the boundary. This item appears when one or more injections have been defined.
reflect
rebounds the particle off the boundary with a change in its momentum as defined by the coefficient of restitution. (See Figure
22.13.1.)
trap
terminates the trajectory calculations and records the fate of the particle as "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure
22.13.2.
escape
reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure
22.13.3.
walljet
indicates that the direction and velocity of the droplet particles are given by the resulting momentum flux, which is a function of the impingement angle. See Figure
22.13.4.
wallfilm
consists of four regimes: stick, rebound, spread, and splash, which are based on the impact energy and wall temperature. Detailed information on the wallfilm model can be found in Section
22.4. The
Number Of Splashed Drops must be specified.
userdefined
specifies a userdefined function to define the discrete phase boundary condition type.
Participates in Solar Ray Tracing
specifies whether or not outflow participate in solar ray tracing.
Discrete Phase BC Function
sets the userdefined function from the dropdown list.
Outlet Vent Panel
The
Outlet Vent panel sets the boundary conditions for an outlet vent zone. It is opened from the
Boundary Conditions panel. See Section
7.11.1 for details about defining the items below.
Controls
Zone Name
sets the name of the zone.
Momentum
contains the momentum parameters.
Gauge Pressure
sets the gauge pressure at the outlet boundary.
Radial Equilibrium Pressure Distribution
enables the radial equilibrium pressure distribution. See Section
7.8.1 for details.
This item appears only for 3D and axisymmetric swirl solvers.
Backflow Direction Specification Method
specifies the method you will use to define the flow direction. If you choose
Direction Vector, you will define the flow direction components, and if you choose
Normal to Boundary or
From Neighboring Cell no inputs are required. See Section
7.3.1 for information on specifying flow direction.
Target massflow
allows you to set mass flow rate as a boundary condition at the outlet.
LossCoefficient
sets the nondimensional loss coefficient used to compute the pressure drop. See Section
7.11.1 for details.
Turbulence
contains the turbulence parameters.
Specification Method
specifies which method will be used to input the turbulence parameters. You can choose
K and Epsilon (

models and RSM only),
K and Omega (

models only),
Intensity and Length Scale,
Intensity and Viscosity Ratio,
Intensity and Hydraulic Diameter, or
Turbulent Viscosity Ratio (SpalartAllmaras model only). See Section
7.2.2 for information about the inputs for each of these methods. (This item will appear only for turbulent flow calculations.)
Backflow Turbulence Kinetic Energy, Backflow Turbulence Dissipation Rate
set values for the turbulence kinetic energy
and its dissipation rate
. These items will appear if you choose
K and Epsilon as the
Specification Method.
Backflow Turbulence Kinetic Energy, Backflow Specific Dissipation Rate
set values for the turbulence kinetic energy
and its specific dissipation rate
. These items will appear if you choose
K and Omega as the
Specification Method.
Backflow Turbulence Intensity, Backflow Turbulence Length Scale
set values for turbulence intensity
and turbulence length scale
. These items will appear if you choose
Intensity and Length Scale as the
Specification Method.
Backflow Turbulence Intensity, Backflow Turbulent Viscosity Ratio
set values for turbulence intensity
and turbulent viscosity ratio
. These items will appear if you choose
Intensity and Viscosity Ratio as the
Specification Method.
Backflow Turbulence Intensity, Backflow Hydraulic Diameter
set values for turbulence intensity
and hydraulic diameter
. These items will appear if you choose
Intensity and Hydraulic Diameter as the
Specification Method.
Backflow Turbulent Viscosity Ratio
sets the value of the backflow turbulent viscosity ratio
. This item will appear if you choose
Turbulent Viscosity Ratio as the
Specification Method.
ReynoldsStress Specification Method
specifies which method will be used to determine the backflow Reynolds stress boundary conditions when the Reynolds stress turbulence model is used. You can choose either
K or Turbulence Intensity or
ReynoldsStress Components. If you choose the former,
FLUENT will compute the Reynolds stresses for you. If you choose the latter, you will explicitly specify the Reynolds stresses yourself. See Section
12.20.3 for details. (This item will appear only for RSM turbulent flow calculations.)
Backflow UU,VV,WW,UV,VW,UW Reynolds Stresses
specify the backflow Reynolds stress components when
ReynoldsStress Components is chosen as the
ReynoldsStress Specification Method.
Thermal
contains the thermal parameters.
Backflow Total Temperature
sets the total temperature of the inflow stream should the flow reverse direction
Radiation
contains the radiation parameters.
Participates in Solar Ray Tracing
specifies whether or not outlet vent participate in solar ray tracing.
External Black Body Temperature Method, Internal Emissivity
set the radiation boundary conditions when you are using the P1 model, the DTRM, the discrete ordinates model, or the S2S model for radiation heat transfer. See Section
13.3.15 for details.
Species
contains the species parameters.
Mean Mixture Fraction, Mixture Fraction Variance
set inlet values for the PDF mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model.)
Secondary Mean Mixture Fraction, Secondary Mixture Fraction Variance
set inlet values for the secondary mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model with two mixture fractions.)
Species Mass Fractions
contains inputs for the mass fractions of defined species. See Section
14.1.5 for details about these inputs. These items will appear only if you are modeling nonreacting multispecies flow or you are using the finiterate reaction formulation.
Backflow Progress Variable
sets the value of the progress variable for premixed turbulent combustion. See Section
16.3.5 for details.
This item will appear only if the premixed or partially premixed combustion model is used.
DPM
contains the discrete phase parameters.
Discrete Phase BC Type
sets the way that the discrete phase behaves with respect to the boundary. This item appears when one or more injections have been defined.
reflect
rebounds the particle off the boundary with a change in its momentum as defined by the coefficient of restitution. (See Figure
22.13.1.)
trap
terminates the trajectory calculations and records the fate of the particle as "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure
22.13.2.
escape
reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure
22.13.3.
walljet
indicates that the direction and velocity of the droplet particles are given by the resulting momentum flux, which is a function of the impingement angle. See Figure
22.13.4.
wallfilm
consists of four regimes: stick, rebound, spread, and splash, which are based on the impact energy and wall temperature. Detailed information on the wallfilm model can be found in Section
22.4. The
Number Of Splashed Drops must be specified.
userdefined
specifies a userdefined function to define the discrete phase boundary condition type.
Discrete Phase BC Function
sets the userdefined function from the dropdown list.
Multiphase
contains the multiphase parameters.
Backflow Granular Temperature
specifies temperature for the solids phase and is proportional to the kinetic energy of the random motion of the particles.
Backflow Volume Fraction
specifies the volume fraction of the secondary phase selected in the
Boundary Conditions panel. This section of the panel will appear when one of the multiphase models is being used. See Section
23.9.8 for details.
UDS
contains the UDS parameters.
UserDefined Scalar Boundary Condition
appears only if user defines scalars are specified.
User Scalarn
specifies the whether the scalar is a specified flux or a specified value.
UserDefined Scalar Boundary Value
appears only if user defines scalars are specified.
User Scalarn
specifies the value of the scalar.
Periodic Panel
The
Periodic panel sets the boundary conditions for a periodic zone. It is opened from the
Boundary Conditions panel. See Section
7.15.2 for details about the items below. See Section
9.4 for information about fullydeveloped periodic flow.
Controls
Zone Name
sets the name of the zone.
Periodic Type
indicates whether the periodicity of the domain is
Translational or
Rotational.
Periodic Pressure Jump
sets the pressure increase/decrease across the periodic boundary. (This item will not appear if the pressurebased (default) solver is used; it is relevant only for the densitybased solvers.)
Porous Jump Panel
The
Porous Jump panel sets the boundary conditions for a porousjump zone. It is opened from the
Boundary Conditions panel. See Section
7.22 for details about the items below.
Controls
Zone Name
sets the name of the zone.
Face Permeability
sets the face permeability coefficient (
in Equation
7.221).
Porous Medium Thickness
sets the thickness of the porous medium (
).
PressureJump Coefficient
sets the pressurejump coefficient (
).
Discrete Phase BC Type
sets the way that the discrete phase behaves with respect to the boundary. This item appears when one or more injections have been defined.
interior
allows the particles to pass through the boundary.
reflect
rebounds the particle off the boundary with a change in its momentum as defined by the coefficient of restitution. (See Figure
22.13.1.)
trap
terminates the trajectory calculations and records the fate of the particle as "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure
22.13.2.
escape
reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure
22.13.3.
walljet
indicates that the direction and velocity of the droplet particles are given by the resulting momentum flux, which is a function of the impingement angle. See Figure
22.13.4.
wallfilm
consists of four regimes: stick, rebound, spread, and splash, which are based on the impact energy and wall temperature. Detailed information on the wallfilm model can be found in Section
22.4. The
Number Of Splashed Drops must be specified.
userdefined
specifies a userdefined function to define the discrete phase boundary condition type.
Discrete Phase BC Function
sets the userdefined function from the dropdown list.
Pressure FarField Panel
The
Pressure FarField panel sets the boundary conditions for a pressure farfield zone. It is opened from the
Boundary Conditions panel. See Section
7.9.1 for details about defining the items below.
Controls
Zone Name
sets the name of the zone.
Momentum
contains the momentum parameters.
Gauge Pressure
sets the farfield gauge static pressure.
Mach Number
sets the farfield Mach number. The Mach number can be subsonic, sonic, or supersonic.
X,Y,ZComponent of FlowDirection
set the farfield flow direction. These items will appear if the selected
Coordinate System is
Cartesian or the model is 2D nonaxisymmetric.
Radial, Tangential, Axial Component of Flow Direction
set the farfield flow direction. These items will appear for 2D axisymmetric cases, or for 3D cases for which the selected
Coordinate System is
Cylindrical or
Local Cylindrical.
Turbulence
contains the turbulence parameters.
Specification Method
specifies which method will be used to input the turbulence parameters. You can choose
K and Epsilon (

models and RSM only),
K and Omega (

models only),
Intensity and Length Scale,
Intensity and Viscosity Ratio,
Intensity and Hydraulic Diameter, or
Turbulent Viscosity Ratio (SpalartAllmaras model only). See Section
7.2.2 for information about the inputs for each of these methods. (This item will appear only for turbulent flow calculations.)
Turbulent Kinetic Energy, Turbulent Dissipation Rate
set values for the turbulence kinetic energy
and its dissipation rate
. These items will appear if you choose
K and Epsilon as the
Specification Method.
Turbulent Kinetic Energy, Specific Dissipation Rate
set values for the turbulence kinetic energy
and its specific dissipation rate
. These items will appear if you choose
K and Omega as the
Specification Method.
Turbulence Intensity, Turbulence Length Scale
set values for turbulence intensity
and turbulence length scale
. These items will appear if you choose
Intensity and Length Scale as the
Specification Method.
Turbulence Intensity, Turbulent Viscosity Ratio
set values for turbulence intensity
and turbulent viscosity ratio
. These items will appear if you choose
Intensity and Viscosity Ratio as the
Specification Method.
Turbulence Intensity, Hydraulic Diameter
set values for turbulence intensity
and hydraulic diameter
. These items will appear if you choose
Intensity and Hydraulic Diameter as the
Specification Method.
Turbulent Viscosity Ratio
sets the value of the turbulent viscosity ratio
. This item will appear if you choose
Turbulent Viscosity Ratio as the
Turbulence Specification Method.
ReynoldsStress Specification Method
specifies which method will be used to determine the Reynolds stress boundary conditions when the Reynolds stress turbulence model is used. You can choose either
K or Turbulence Intensity or
ReynoldsStress Components. If you choose the former,
FLUENT will compute the Reynolds stresses for you. If you choose the latter, you will explicitly specify the Reynolds stresses yourself. See Section
12.20.3 for details. (This item will appear only for RSM turbulent flow calculations.)
UU,VV,WW,UV,VW,UW Reynolds Stresses
specify the Reynolds stress components when
ReynoldsStress Components is chosen as the
ReynoldsStress Specification Method.
Thermal
contains the thermal parameters.
Temperature
sets the farfield static temperature.
Radiation
contains the radiation parameters.
External Black Body Temperature Method, Internal Emissivity
set the radiation boundary conditions when you are using the P1 model, the DTRM, the discrete ordinates model, or the S2S model for radiation heat transfer. See Section
13.3.15 for details.
Participates in Solar Ray Tracing
specifies whether or not pressure farfield participate in solar ray tracing.
Species
contains the species parameters.
Species Mass Fractions
contains inputs for the mass fractions of defined species. See Section
14.1.5 for details about these inputs. (These items will appear only if you are modeling nonreacting multispecies flow or you are using the finiterate reaction formulation.)
Mean Mixture Fraction, Mixture Fraction Variance
set inlet values for the PDF mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model.)
Secondary Mean Mixture Fraction, Secondary Mixture Fraction Variance
set inlet values for the secondary mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model with two mixture fractions.)
Progress Variable
sets the value of the progress variable for premixed turbulent combustion. See Section
16.3.5 for details.
This item will appear only if the premixed or partially premixed combustion model is used.
UDS
contains the UDS parameters.
UserDefined Scalar Boundary Condition
appears only if user defines scalars are specified.
User Scalarn
specifies the whether the scalar is a specified flux or a specified value.
UserDefined Scalar Boundary Value
appears only if user defines scalars are specified.
User Scalarn
specifies the value of the scalar.
DPM
contains the discrete phase parameters.
Discrete Phase BC Type
sets the way that the discrete phase behaves with respect to the boundary. This item appears when one or more injections have been defined.
reflect
rebounds the particle off the boundary with a change in its momentum as defined by the coefficient of restitution. (See Figure
22.13.1.)
trap
terminates the trajectory calculations and records the fate of the particle as "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure
22.13.2.
escape
reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure
22.13.3.
walljet
indicates that the direction and velocity of the droplet particles are given by the resulting momentum flux, which is a function of the impingement angle. See Figure
22.13.4.
wallfilm
consists of four regimes: stick, rebound, spread, and splash, which are based on the impact energy and wall temperature. Detailed information on the wallfilm model can be found in Section
22.4. The
Number Of Splashed Drops must be specified.
userdefined
specifies a userdefined function to define the discrete phase boundary condition type.
Discrete Phase BC Function
sets the userdefined function from the dropdown list.
Pressure Inlet Panel
The
Pressure Inlet panel sets the boundary conditions for a pressure inlet zone. It is opened from the
Boundary Conditions panel. See Section
7.3.1 for details about defining the items below.
Controls
Zone Name
sets the name of the zone.
Momentum
contains the momentum parameters.
Gauge Total Pressure
sets the gauge total (or stagnation) pressure of the inflow stream. If you are using moving reference frames, see Section
7.3.1 for information about relative and absolute total pressure.
Supersonic/Initial Gauge Pressure
sets the static pressure on the boundary when the flow becomes (locally) supersonic. It is also used to compute initial values for pressure, temperature, and velocity if the pressure inlet boundary condition is selected for computing initial values (see Section
25.14.1).
Direction Specification Method
specifies the method you will use to define the flow direction. If you choose
Direction Vector, you will define the flow direction components, and if you choose
Normal to Boundary no inputs are required. See Section
7.3.1 for information on specifying flow direction.
Coordinate System
specifies whether
Cartesian,
Cylindrical, or
Local Cylindrical vector components will be input. This item will appear only for 3D cases in which you have selected
Direction Vector as the
Direction Specification Method.
X,Y,ZComponent of Flow Direction
set the direction of the flow at the inlet boundary. These items will appear if the selected
Coordinate System is
Cartesian or the model is 2D nonaxisymmetric.
Radial, Tangential, Axial Component of Flow Direction
set the direction of the flow at the inlet boundary. These items will appear for 2D axisymmetric cases, or for 3D cases for which the selected
Coordinate System is
Cylindrical or
Local Cylindrical.
X,Y,ZComponent of Axis Direction
sets the direction of the axis. These items will appear if the selected
Coordinate System is
Local Cylindrical.
X,Y,ZCoordinate of Axis Origin
sets the location of the axis origin. These items will appear if the selected
Coordinate System is
Local Cylindrical.
Turbulence
contains the turbulence parameters.
Specification Method
specifies which method will be used to input the turbulence parameters. You can choose
K and Epsilon (

models and RSM only),
K and Omega (

models only),
Intensity and Length Scale,
Intensity and Viscosity Ratio,
Intensity and Hydraulic Diameter, or
Turbulent Viscosity Ratio (SpalartAllmaras model only). See Section
7.2.2 for information about the inputs for each of these methods. (This item will appear only for turbulent flow calculations.)
Turbulence Kinetic Energy, Turbulence Dissipation Rate
set values for the turbulence kinetic energy
and its dissipation rate
. These items will appear if you choose
K and Epsilon as the
Specification Method.
Turbulence Kinetic Energy, Specific Dissipation Rate
set values for the turbulence kinetic energy
and its specific dissipation rate
. These items will appear if you choose
K and Omega as the
Specification Method.
Turbulence Intensity, Turbulence Length Scale
set values for turbulence intensity
and turbulence length scale
. These items will appear if you choose
Intensity and Length Scale as the
Specification Method.
Turbulence Intensity, Turbulent Viscosity Ratio
set values for turbulence intensity
and turbulent viscosity ratio
. These items will appear if you choose
Intensity and Viscosity Ratio as the
Specification Method.
Turbulence Intensity, Hydraulic Diameter
set values for turbulence intensity
and hydraulic diameter
. These items will appear if you choose
Intensity and Hydraulic Diameter as the
Specification Method.
Turbulent Viscosity Ratio
sets the value of the turbulent viscosity ratio
. This item will appear if you choose
Turbulent Viscosity Ratio as the
Specification Method.
ReynoldsStress Specification Method
specifies which method will be used to determine the Reynolds stress boundary conditions when the Reynolds stress turbulence model is used. You can choose either
K or Turbulence Intensity or
ReynoldsStress Components. If you choose the former,
FLUENT will compute the Reynolds stresses for you. If you choose the latter, you will explicitly specify the Reynolds stresses yourself. See Section
12.20.3 for details. (This item will appear only for RSM turbulent flow calculations.)
UU,VV,WW,UV,VW,UW Reynolds Stresses
specify the Reynolds stress components when
ReynoldsStress Components is chosen as the
ReynoldsStress Specification Method.
Thermal
contains the thermal parameters.
Total Temperature
sets the total temperature of the inflow stream. If you are using moving reference frames, see Section
7.3.1 for information about relative and absolute total temperature.
Radiation
contains the radiation parameters.
External Black Body Temperature Method, Internal Emissivity
set the radiation boundary conditions when you are using the P1 model, the DTRM, the discrete ordinates model, or the S2S model for radiation heat transfer. See Section
13.3.15 for details.
Participates in Solar Ray Tracing
specifies whether or not pressure inlet participate in solar ray tracing.
Species
contains the species parameters.
Species Mass Fractions
contains inputs for the mass fractions of defined species. See Section
14.1.5 for details about these inputs. (These items will appear only if you are modeling nonreacting multispecies flow or you are using the finiterate reaction formulation.)
Mean Mixture Fraction, Mixture Fraction Variance
set inlet values for the PDF mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model.)
Secondary Mean Mixture Fraction, Secondary Mixture Fraction Variance
set inlet values for the secondary mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model with two mixture fractions.)
Progress Variable
sets the value of the progress variable for premixed turbulent combustion. See Section
16.3.5 for details.
This item will appear only if the premixed or partially premixed combustion model is used.
DPM
contains the discrete phase parameters.
Discrete Phase BC Type
sets the way that the discrete phase behaves with respect to the boundary. This item appears when one or more injections have been defined.
reflect
rebounds the particle off the boundary with a change in its momentum as defined by the coefficient of restitution. (See Figure
22.13.1.)
trap
terminates the trajectory calculations and records the fate of the particle as "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure
22.13.2.
escape
reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure
22.13.3.
walljet
indicates that the direction and velocity of the droplet particles are given by the resulting momentum flux, which is a function of the impingement angle. See Figure
22.13.4.
wallfilm
consists of four regimes: stick, rebound, spread, and splash, which are based on the impact energy and wall temperature. Detailed information on the wallfilm model can be found in Section
22.4. The
Number Of Splashed Drops must be specified.
userdefined
specifies a userdefined function to define the discrete phase boundary condition type.
Discrete Phase BC Function
sets the userdefined function from the dropdown list.
Multiphase
contains the multiphase parameters.
Granular Temperature
specifies temperature for the solids phase and is proportional to the kinetic energy of the random motion of the particles.
Volume Fraction
specifies the volume fraction of the secondary phase selected in the
Boundary Conditions panel. This section of the panel will appear when one of the multiphase models is being used. See Section
23.9.8 for details.
UDS
contains the UDS parameters.
UserDefined Scalar Boundary Condition
appears only if user defines scalars are specified.
User Scalarn
specifies the whether the scalar is a specified flux or a specified value.
UserDefined Scalar Boundary Value
appears only if user defines scalars are specified.
User Scalarn
specifies the value of the scalar.
Pressure Outlet Panel
The
Pressure Outlet panel sets the boundary conditions for a pressure outlet zone. It is opened from the
Boundary Conditions panel. See Section
7.8.1 for details about defining the items below.
Controls
Zone Name
sets the name of the zone.
Momentum
contains the momentum parameters.
Gauge Pressure
sets the gauge pressure at the outflow boundary.
Radial Equilibrium Pressure Distribution
enables the radial equilibrium pressure distribution. See Section
7.8.1 for details.
This item appears only for 3D and axisymmetric swirl solvers.
Backflow Direction Specification Method
sets the direction of the inflow stream should the flow reverse direction. If you choose
Direction Vector, you will define the flow direction components, and if you choose
Normal to Boundary or
From Neighboring Cell, no inputs are required. See Section
7.8.1 for information on specifying flow direction.
Target Mass Flow Rate
allows you to set mass flow rate as a boundary condition at the outlet.
Turbulence
contains the turbulence parameters.
Specification Method
specifies which method will be used to input the turbulence parameters. You can choose
K and Epsilon (

models and RSM only),
K and Omega (

models only),
Intensity and Length Scale,
Intensity and Viscosity Ratio,
Intensity and Hydraulic Diameter, or
Turbulent Viscosity Ratio (SpalartAllmaras model only). See Section
7.2.2 for information about the inputs for each of these methods. (This item will appear only for turbulent flow calculations.)
Backflow Turbulence Kinetic Energy, Backflow Turbulence Dissipation Rate
set values for the turbulence kinetic energy
and its dissipation rate
. These items will appear if you choose
K and Epsilon as the
Specification Method.
Backflow Turbulence Kinetic Energy, Backflow Specific Dissipation Rate
set values for the turbulence kinetic energy
and its specific dissipation rate
. These items will appear if you choose
K and Omega as the
Specification Method.
Backflow Turbulence Intensity, Backflow Turbulence Length Scale
set values for turbulence intensity
and turbulence length scale
. These items will appear if you choose
Intensity and Length Scale as the
Specification Method.
Backflow Turbulence Intensity, Backflow Turbulent Viscosity Ratio
set values for turbulence intensity
and turbulent viscosity ratio
. These items will appear if you choose
Intensity and Viscosity Ratio as the
Specification Method.
Backflow Turbulence Intensity, Backflow Hydraulic Diameter
set values for turbulence intensity
and hydraulic diameter
. These items will appear if you choose
Intensity and Hydraulic Diameter as the
Specification Method.
Backflow Turbulent Viscosity Ratio
sets the value of the backflow turbulent viscosity ratio
. This item will appear if you choose
Turbulent Viscosity Ratio as the
Specification Method.
ReynoldsStress Specification Method
specifies which method will be used to determine the backflow Reynolds stress boundary conditions when the Reynolds stress turbulence model is used. You can choose either
K or Turbulence Intensity or
ReynoldsStress Components. If you choose the former,
FLUENT will compute the Reynolds stresses for you. If you choose the latter, you will explicitly specify the Reynolds stresses yourself. See Section
12.20.3 for details. (This item will appear only for RSM turbulent flow calculations.)
Backflow UU,VV,WW,UV,VW,UW Reynolds Stresses
specify the backflow Reynolds stress components when
ReynoldsStress Components is chosen as the
ReynoldsStress Specification Method.
Thermal
contains the thermal parameters.
Backflow Total Temperature
sets the total temperature of the inflow stream should the flow reverse direction
Radiation
contains the radiation parameters.
External Black Body Temperature Method, Internal Emissivity
set the radiation boundary conditions when you are using the P1 model, the DTRM, the discrete ordinates model, or the S2S model for radiation heat transfer. See Section
13.3.15 for details.
Participates in Solar Ray Tracing
specifies whether or not pressure outlet participate in solar ray tracing.
Species
contains the species parameters.
Mean Mixture Fraction, Mixture Fraction Variance
set inlet values for the PDF mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model.)
Secondary Mean Mixture Fraction, Secondary Mixture Fraction Variance
set inlet values for the secondary mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model with two mixture fractions.)
Species Mass Fractions
contains inputs for the mass fractions of defined species. See Section
14.1.5 for details about these inputs. These items will appear only if you are modeling nonreacting multispecies flow or you are using the finiterate reaction formulation.
Backflow Progress Variable
sets the value of the progress variable for premixed turbulent combustion. See Section
16.3.5 for details.
This item will appear only if the premixed or partially premixed combustion model is used.
DPM
contains the discrete phase parameters.
Discrete Phase BC Type
sets the way that the discrete phase behaves with respect to the boundary. This item appears when one or more injections have been defined.
reflect
rebounds the particle off the boundary with a change in its momentum as defined by the coefficient of restitution. (See Figure
22.13.1.)
trap
terminates the trajectory calculations and records the fate of the particle as "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure
22.13.2.
escape
reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure
22.13.3.
walljet
indicates that the direction and velocity of the droplet particles are given by the resulting momentum flux, which is a function of the impingement angle. See Figure
22.13.4.
wallfilm
consists of four regimes: stick, rebound, spread, and splash, which are based on the impact energy and wall temperature. Detailed information on the wallfilm model can be found in Section
22.4. The
Number Of Splashed Drops must be specified.
userdefined
specifies a userdefined function to define the discrete phase boundary condition type.
Discrete Phase BC Function
sets the userdefined function from the dropdown list.
Multiphase
contains the multiphase parameters.
Backflow Granular Temperature
specifies temperature for the solids phase and is proportional to the kinetic energy of the random motion of the particles.
Backflow Volume Fraction
specifies the volume fraction of the secondary phase selected in the
Boundary Conditions panel. This section of the panel will appear when one of the multiphase models is being used. See Section
23.9.8 for details.
UDS
contains the UDS parameters.
UserDefined Scalar Boundary Condition
appears only if user defines scalars are specified.
User Scalarn
specifies the whether the scalar is a specified flux or a specified value.
UserDefined Scalar Boundary Value
appears only if user defines scalars are specified.
User Scalarn
specifies the value of the scalar.
Radiator Panel
The
Radiator panel sets the boundary conditions for a radiator model zone. It is opened from the
Boundary Conditions panel. See Section
7.21.2 for details about the items below.
Controls
Zone Name
sets the name of the zone.
Loss Coefficient
specifies the loss coefficient as a constant value or as a polynomial, piecewiselinear, or piecewisepolynomial function of velocity. See Section
7.21.2 for details.
Heat Transfer Coefficient
specifies the heattransfer coefficient as a constant value or as a polynomial, piecewiselinear, or piecewisepolynomial function of velocity. See Section
7.21.2 for details.
Temperature
sets the temperature used to compute heat flux from the radiator using the
HeatTransferCoefficient. If
Temperature is zero, the
Heat Flux condition is used instead.
Heat Flux
sets the heat flux at the radiator surface (used only when
Temperature is zero).
Discrete Phase BC Type
sets the way that the discrete phase behaves with respect to the boundary. This item appears when one or more injections have been defined.
interior
allows the particles to pass through the boundary.
reflect
rebounds the particle off the boundary with a change in its momentum as defined by the coefficient of restitution. (See Figure
22.13.1.)
trap
terminates the trajectory calculations and records the fate of the particle as "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure
22.13.2.
escape
reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure
22.13.3.
walljet
indicates that the direction and velocity of the droplet particles are given by the resulting momentum flux, which is a function of the impingement angle. See Figure
22.13.4.
wallfilm
consists of four regimes: stick, rebound, spread, and splash, which are based on the impact energy and wall temperature. Detailed information on the wallfilm model can be found in Section
22.4. The
Number Of Splashed Drops must be specified.
userdefined
specifies a userdefined function to define the discrete phase boundary condition type.
Discrete Phase BC Function
sets the userdefined function from the dropdown list.
Solid Panel
The
Solid panel sets the boundary conditions for a solid cell zone. It is opened from the
Boundary Conditions panel. See Section
7.18.1 for details about the items below.
Controls
Zone Name
sets the name of the zone.
Material Name
selects the material type of the solid. Materials are defined with the
Materials panel.
Source Terms
enables the specification of a volumetric source of energy. When you turn on this option, the
Source Term tab will allow you to input the value for the energy source. See Section
7.28 for details.
Fixed Values
enables the fixing of the value of temperature in the solid zone, rather than computing it during the calculation. See Section
7.27 for details.
You can fix the value of temperature only if you are using the pressurebased solver.
Participates In Radiation
specifies whether or not the solid zone participates in radiation. This option appears when you are using the DO model for radiation.
Motion
lists the parameters that define motion.
RotationAxis Origin
specifies the origin for the axis of rotation of solid zone. See Section
7.18.1 for details. This item will appear only for 3D and 2D nonaxisymmetric models.
RotationAxis Direction
specifies the direction vector for the solid zone's axis of rotation. See Section
7.18.1 for details. This item will appear only for 3D models.
Motion Type
specifies zone motion for a rotating or translating reference frame or for a sliding zone in a sliding mesh problem. The default selection of
Stationary indicates that the zone is not moving. To define the motion of a moving reference frame for the zone, select
Moving Reference Frame and specify the items below in the expanded portion of the panel. See Section
10.710.10.1, or
10.10.2 for details. To define zone motion for a moving (sliding) mesh, select
Moving Mesh and set the appropriate parameters below. See Section
11.4.2 for details.
Rotational Velocity
contains an input field for the rotational
Speed of the zone. This item will appear if you select
Moving Reference Frame or
Moving Mesh in the
Motion Type list.
Translational Velocity
contains inputs for the
X,
Y, and
Z velocities of the zone. This item will appear if you select
Moving Reference Frame or
Moving Mesh in the
Motion Type list.
Source Term
lists the parameters for volumetric source of energy.
Energy
displays the total number of energy sources used.
User Scalar n
displays the total number of scalars used.
Fixed Values
lists the parameters that can be declared as fixed during the calculation.
Temperature
specifies the fixed value for temperature.
User Scalar n
specifies the fixed value for user scalar.
Symmetry Panel
The
Symmetry panel can be used to modify the name of a symmetry zone; there are no conditions to be set. It is opened from the
Boundary Conditions panel. See Section
7.14 for information about symmetry boundaries.
Controls
Zone Name
sets the name of the zone.
Phase
displays the name of the phase. This item is available only for multiphase flows.
Velocity Inlet Panel
The
Velocity Inlet panel sets the boundary conditions for a velocity inlet zone. It is opened from the
Boundary Conditions panel. See Section
7.4.1 for details about defining the items below.
Controls
Zone Name
sets the name of the zone.
Momentum
contains the momentum parameters.
Velocity Specification Method
sets the method used to define the inflow velocity.
Magnitude and Direction
allows specification in terms of a
Velocity Magnitude and
FlowDirection.
Components
allows specification in terms of the Cartesian, cylindrical, or local cylindrical velocity components.
Magnitude, Normal to Boundary
allows specification of a
Velocity Magnitude normal to the boundary.
Reference Frame
specifies relative or absolute velocity inputs. You can choose to enter
Absolute velocities or velocities
Relative to Adjacent Cell Zone. If you are not using moving reference frames, both options are equivalent, so you need not choose.
Coordinate System
specifies whether
Cartesian,
Cylindrical, or
Local Cylindrical velocities will be input. This item will appear only for 3D cases in which you have selected
Magnitude and Direction or
Components as the
Velocity Specification Method.
X,Y,ZVelocity
set the components of the velocity vector at the inflow boundary. These items will appear for 2D nonaxisymmetric models, or for 3D models if you select the
Components option as the
Velocity Specification Method and
Cartesian as the
Coordinate System.
Radial, Tangential, AxialVelocity
set the components of the velocity vector at the inflow boundary. These items will appear for 3D models if you select the
Components option as the
Velocity Specification Method and
Cylindrical or
Local Cylindrical as the
Coordinate System.
Axial, Radial, SwirlVelocity
set the components of the velocity vector at the inflow boundary. These items will appear for 2D axisymmetric models.
SwirlVelocity will appear only for 2D axisymmetric swirl models.
Angular Velocity
specifies the angular velocity
for a 3D flow. This item will appear for a 3D model if you select the
Components option as the
Velocity Specification Method and
Cylindrical or
Local Cylindrical as the
Coordinate System.
Swirl Angular Velocity
specifies the swirl angular velocity
for an axisymmetric swirling flow. This item will appear for an axisymmetric swirl model if you choose
Components as the
Velocity Specification Method.
Velocity Magnitude
sets the magnitude of the velocity vector at the inflow boundary. This item will appear if you select the
Magnitude and Direction or
Magnitude, Normal to Boundary option as the
Velocity Specification Method.
X,Y,ZComponent of FlowDirection
set the direction of the velocity vector at the inflow boundary. These items will appear for 2D nonaxisymmetric models if you select the
Magnitude and Direction option as the
Velocity Specification Method, or for 3D models if you select the
Magnitude and Direction option as the
Velocity Specification Method and
Cartesian as the
Coordinate System.
Radial, Tangential, AxialComponent of Flow Direction
set the direction of the velocity vector at the inlet boundary. These items will appear for 3D models if you select the
Magnitude and Direction option as the
Velocity Specification Method and
Cylindrical or
Local Cylindrical as the
Coordinate System, or for 2D axisymmetric models.
TangentialVelocity will appear only for 2D axisymmetric swirl models.
X,Y,ZComponent of Axis Direction
sets the direction of the axis. These items will appear if the selected
Coordinate System is
Local Cylindrical.
X,Y,ZCoordinate of Axis Origin
sets the location of the axis origin. These items will appear if the selected
Coordinate System is
Local Cylindrical.
Outflow Gauge Pressure
specifies the pressure to be used as the pressure outlet condition if flow exits the domain at any face on the velocity inlet boundary. (Note that this effect is similar to that of the "velocity farfield'' boundary that was available in
RAMPANT 3.)
This item appears only for the densitybased solvers.
Turbulence
contains the turbulence parameters.
Specification Method
specifies which method will be used to input the turbulence parameters. You can choose
K and Epsilon (

models and RSM only),
K and Omega (

models only),
Intensity and Length Scale,
Intensity and Viscosity Ratio,
Intensity and Hydraulic Diameter, or
Turbulent Viscosity Ratio (SpalartAllmaras model only). See Section
7.2.2 for information about the inputs for each of these methods. (This item will appear only for turbulent flow calculations.)
Turbulence Kinetic Energy, Turbulence Dissipation Rate
set values for the turbulence kinetic energy
and its dissipation rate
. These items will appear if you choose
K and Epsilon as the
Specification Method.
Turbulence Kinetic Energy, Specific Dissipation Rate
set values for the turbulence kinetic energy
and its specific dissipation rate
. These items will appear if you choose
K and Omega as the
Specification Method.
Turbulence Intensity, Turbulence Length Scale
set values for turbulence intensity
and turbulence length scale
. These items will appear if you choose
Intensity and Length Scale as the
Specification Method.
Turbulence Intensity, Turbulent Viscosity Ratio
set values for turbulence intensity
and turbulent viscosity ratio
. These items will appear if you choose
Intensity and Viscosity Ratio as the
Specification Method.
Turbulence Intensity, Hydraulic Diameter
set values for turbulence intensity
and hydraulic diameter
. These items will appear if you choose
Intensity and Hydraulic Diameter as the
Specification Method.
Turbulent Viscosity Ratio
sets the value of the turbulent viscosity ratio
. This item will appear if you choose
Turbulent Viscosity Ratio as the
Specification Method.
Turbulence Intensity
sets the value of the turbulence intensity
for the LES model.
ReynoldsStress Specification Method
specifies which method will be used to determine the Reynolds stress boundary conditions when the Reynolds stress turbulence model is used. You can choose either
K or Turbulence Intensity or
ReynoldsStress Components. If you choose the former,
FLUENT will compute the Reynolds stresses for you. If you choose the latter, you will explicitly specify the Reynolds stresses yourself. See Section
12.20.3 for details. (This item will appear only for RSM turbulent flow calculations.)
UU,VV,WW,UV,VW,UW Reynolds Stresses
specify the Reynolds stress components when
ReynoldsStress Components is chosen as the
ReynoldsStress Specification Method.
Thermal
contains the thermal parameters.
Temperature
specifies the static temperature of the flow.
Radiation
contains the radiation parameters.
Participates in Solar Ray Tracing
specifies whether or not velocity inlet participate in solar ray tracing.
External Black Body Temperature Method, Internal Emissivity
set the radiation boundary conditions when you are using the P1 model, the DTRM, the discrete ordinates model, or the S2S model for radiation heat transfer. See Section
13.3.15 for details.
Species
contains the species parameters.
Species Mass Fractions
contains inputs for the mass fractions of defined species. See Section
14.1.5 for details about these inputs. These items will appear only if you are modeling nonreacting multispecies flow or you are using the finiterate reaction formulation.
Mean Mixture Fraction, Mixture Fraction Variance
set inlet values for the PDF mixture fraction and its variance. These items will appear only if you are using the nonpremixed or partially premixed combustion model.
Secondary Mean Mixture Fraction, Secondary Mixture Fraction Variance
set inlet values for the secondary mixture fraction and its variance. (These items will appear only if you are using the nonpremixed or partially premixed combustion model with two mixture fractions.)
Progress Variable
sets the value of the progress variable for premixed turbulent combustion. See Section
16.3.5 for details.
This item will appear only if the premixed or partially premixed combustion model is used.
DPM
contains the discrete phase parameters.
Discrete Phase BC Type
sets the way that the discrete phase behaves with respect to the boundary. This item appears when one or more injections have been defined.
reflect
rebounds the particle off the boundary with a change in its momentum as defined by the coefficient of restitution. (See Figure
22.13.1.)
trap
terminates the trajectory calculations and records the fate of the particle as "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure
22.13.2.
escape
reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure
22.13.3.
walljet
indicates that the direction and velocity of the droplet particles are given by the resulting momentum flux, which is a function of the impingement angle. See Figure
22.13.4.
wallfilm
consists of four regimes: stick, rebound, spread, and splash, which are based on the impact energy and wall temperature. Detailed information on the wallfilm model can be found in Section
22.4. The
Number Of Splashed Drops must be specified.
userdefined
specifies a userdefined function to define the discrete phase boundary condition type.
Discrete Phase BC Function
sets the userdefined function from the dropdown list.
Multiphase
contains the multiphase parameters.
Volume Fraction
specifies the volume fraction of the secondary phase selected in the
Boundary Conditions panel. This section of the panel will appear when one of the multiphase models is being used. See Section
23.9.8 for details.
UDS
contains the UDS parameters.
UserDefined Scalar Boundary Condition
appears only if user defines scalars are specified.
User Scalarn
specifies the whether the scalar is a specified flux or a specified value.
UserDefined Scalar Boundary Value
appears only if user defines scalars are specified.
User Scalarn
specifies the value of the scalar.
Wall Panel
The
Wall panel sets the boundary conditions for a wall zone. It is opened from the
Boundary Conditions panel. See Section
7.13.1 for details about defining the items below.
Controls
Zone Name
sets the name of the zone.
Adjacent Cell Zone
shows the name of the cell zone adjacent to the wall. (This is for informational use only; you cannot edit this field.)
Momentum
displays the momentum boundary conditions.
Wall Motion
contains options for specifying whether or not the wall is moving.
Stationary Wall
specifies that the wall is not moving relative to the adjacent cell zone.
Moving Wall
enables specification of the tangential wall motion. Tangential wall motion is applicable only to viscous flows. Since the inviscid slip condition decouples the tangential wall velocity from the governing equations, tangential wall motion has no effect on inviscid flow.
Motion
contains inputs related to wall motion. See Section
7.13.1 for details.
Relative to Adjacent Cell Zone
enables the specification of a wall velocity relative to the velocity of the adjacent cell zone. (If the adjacent cell zone is not moving, this is equivalent to
Absolute.)
Absolute
enables the specification of an absolute wall velocity,
Translational
enables the specification of a translational wall velocity.
Rotational
enables the specification of a rotational wall velocity.
Components
enables the specification of wall velocity components.
Speed
sets the translational or rotational speed of the wall (depending on whether you selected
Translational or
Rotational).
Direction
sets the direction vector of the translational velocity. (This item will appear if you have chosen the
Translational option.)
RotationAxis Origin
sets the coordinates of the origin of the axis of rotation, thereby determining the location of the axis. (This item will appear if you have chosen the
Rotational option for a nonaxisymmetric case.)
RotationAxis Direction
sets the direction vector for the axis of rotation. (This item will appear if you have chosen the
Rotational option for a nonaxisymmetric case.)
Velocity Components
sets the
X,
Y, and
ZVelocity components of the wall motion. (This item will appear if you have chosen the
Components option.)
Shear Condition
contains options for specifying the shear conditions at the wall.
No Slip
specifies a noslip condition at the wall. No further inputs are required.
Specified Shear
enables specification of zero or nonzero shear. See Section
7.13.1 for details. This option is not available for moving walls.
Marangoni Stress
enables the specification of shear stress caused by the variation of surface tension due to temperature. This option is not available for moving walls.
Shear Stress
contains inputs related to wall shear. These items will appear when
Specified Shear is selected as the
Shear Condition. See Section
7.13.1 for details.
XComponent, YComponent, ZComponent, Swirl Component
specify the
,
, and
or swirl components of shear for a slip wall.
Swirl Component is available only for axisymmetric swirl cases.
Marangoni Stress
contains inputs related to Marangoni stress. This item will appear when
Marangoni Stress is selected as the
Shear Condition. See Section
7.13.1 for details.
Surface Tension Gradient
specifies the surface tension gradient with respect to temperature (
in Equation
7.131).
Wall Roughness
contains inputs for defining wall roughness in turbulent calculations. See Section
7.13.1 for details.
Roughness Height
sets the roughness height
(see Section
7.13.1 for details).
Roughness Constant
sets the roughness constant
(see Section
7.13.1 for details).
Wall Adhesion
contains inputs related to wall adhesion. This section of the panel will appear if you are using the VOF model and have enabled wall adhesion in the
Phase Interaction panel.
Contact Angles
specifies the contact angle at the wall for each pair of phases (
in Figure
23.3.3). See Section
23.9.8 for details.
Thermal
contains the thermal parameters. This tab is available only when the energy equation is turned on.
Thermal Conditions
contains radio buttons for selecting the thermal boundary condition type. See Section
7.13.1 for details about these inputs:
Heat Flux
selects a specified heat flux condition.
Temperature
selects a specified wall temperature condition.
Convection
selects a convective heat transfer boundary condition model.
Radiation
selects an external radiation boundary condition.
Mixed
selects a combined convection/external radiation boundary condition.
Coupled
selects a coupled heat transfer condition. It is applicable only to walls that form the interface between two regions (such as the fluid/solid interface for a conjugate heat transfer problem).
Once a condition type has been selected, the appropriate conditions can be specified.
Heat Flux
sets the wall heat flux to be used for the
Heat Flux condition. A specification of zero
Heat Flux is simply the adiabatic condition (no heat transfer). A positive value of heat flux implies that heat is input
into the domain.
Temperature
sets the wall temperature to be used for the
Temperature condition.
Heat Transfer Coefficient
sets the convective heat transfer coefficient to be used for the
Convection condition (
in Equation
7.1312).
Free Stream Temperature
sets the reference or free stream temperature to be used for the
Convection condition (
in Equation
7.1312).
External Emissivity
sets the emissivity of the external wall to be used for the
Radiation condition (
in Equation
7.1313).
External Radiation Temperature
sets the temperature of the external radiation source/sink to be used for the
Radiation condition (
in Equation
7.1313).
Internal Emissivity
sets the internal emissivity of the wall. This item will appear only if you are using the P1 model, the DTRM, the discrete ordinates model, or the S2S model for radiation heat transfer. (Note that it will not appear if you are using the nongray discrete ordinates model. In this case, you will enter the
Internal Emissivity for each band under
Radiation.)
Wall Thickness
sets the thickness of the wall for calculation of thinwall thermal resistance. (See Section
7.13.1 for details.)
Heat Generation Rate
sets the rate of heat generation in the wall.
Contact Resistance
sets the contact resistance (
in Equation
24.216) at the wall. See Section
24.3 for details. This item appears only when the solidification/melting model is used.
Material Name
sets the material type of the wall. The conductivity of the material is used for the calculation of thinwall thermal resistance. (See Section
7.13.1 for details.)
Material is used only when
Wall Thickness is nonzero. Materials are defined with the
Materials panel.
Shell Conduction
enables shell conduction for the wall. See Section
7.13.1 for details.
Radiation
displays the boundary conditions for the DO radiation model at the wall. This tab is available only if you are using the discrete ordinates radiation model. See Section
13.3.15 for details.
BC Type
contains a dropdown list of available radiation boundary condition types. The available options are
opaque and
semitransparent.
Internal Emissivity
specifies the internal emissivity of the wall in each wavelength band. This item will appear only if you are using the nongray discrete ordinates radiation model and you have selected
opaque as the
BC Type.
Diffuse Fraction
specifies the fraction of the irradiation that is to be treated as diffuse. By default, the
Diffuse Fraction is set to 1, indicating that all of the irradiation is diffuse. If the nongray DO model is being used, the
Diffuse Fraction can be specified for each band.
Beam Width
specifies the beam width for an external semitransparent wall in terms of the
Theta and
Phi extents. This item will appear only if you are using the discrete ordinates radiation model and you have selected
semitransparent as the
BC Type.
Beam Direction
specifies the beam direction as an
X,Y,Z vector. This item will appear only if you are using the discrete ordinates radiation model and you have selected
semitransparent as the
BC Type.
Irradiation
specifies the value of the irradiation flux. If the nongray DO model is being used, a constant
Irradiation can be specified for each band.
This item will appear only if you are using the discrete ordinates radiation model and you have selected
semitransparent as the
BC Type.
Species
contains the species parameters. This tab is available only if you have enabled the
Species Transport model in the
Species Model panel.
Reaction
activates reactions at the wall. This item will appear only if you have enabled any of the reactions in the
Species Model panel.
Reaction Mechanisms
allows you to specify a defined group, or mechanism, of available reactions. This item will appear only if the
Reaction option has been turned on. See Section
14.1.4 for details about defining reaction mechanisms.
Species Boundary Condition
contains options for the specification of species boundary conditions. See Section
7.13.1 for details.
Zero Diffusive Flux
indicates a zeroflux condition for a species. This is the default condition.
Specified Mass Fraction
indicates that the species mass fraction will be specified.
Species Mass Fractions
contains inputs for the species mass fractions of any species for which you have selected
Species Mass Fraction as the
Species Boundary Condition.
DPM
contains the discrete phase parameters. This tab is available only if you have defined at least one injection.
Discrete Phase Model Conditions
contains inputs for setting the fate of particle trajectories at the wall. These options will appear when one or more injections have been defined. See Section
22.13 for details.
Boundary Cond. Type
sets the way that the discrete phase behaves with respect to the boundary.
reflect
rebounds the particle off the boundary with a change in its momentum as defined by the coefficients of restitution. (See Figure
22.13.1.)
trap
terminates the trajectory calculations and records the fate of the particle as "trapped''. In the case of evaporating droplets, their entire mass instantaneously passes into the vapor phase and enters the cell adjacent to the boundary. See Figure
22.13.2.
escape
reports the particle as having "escaped'' when it encounters the boundary. Trajectory calculations are terminated. See Figure
22.13.3.
userdefined
specifies a userdefined function to define the discrete phase boundary condition type.
Boundary Cond. Function
sets the userdefined function from the dropdown list.
Discrete Phase Reflection Coefficients
determine the behavior of reflecting particles. This item appears when
reflect is chosen as the
Boundary Cond. Type. See Section
22.13.1 for details on setting the following items.
Normal
sets the type of function for the normal coefficient of restitution. This function can be
constant,
piecewiselinear,
piecewisepolynomial, or
polynomial.
Tangent
sets the type of function for the tangential coefficient of restitution. This function can be
constant,
piecewiselinear,
piecewisepolynomial, or
polynomial.
Erosion Model
contains inputs for erosion calculations. See Section
22.13.1 for details about these items.
Impact Angle Function
specifies the value of
in Equation
22.51.
Diameter Function
specifies the value of
in Equation
22.51.
Velocity Exponent Function
specifies the value of
in Equation
22.51.
UDS
displays the boundary conditions for userdefined scalars (UDSs) at the wall. This tab is available only if you have specified a nonzero number of userdefined scalars in the
UserDefined Scalars panel.
User Defined Scalar Boundary Condition
contains options for the specification of UDS boundary conditions. See the separate
UDF Manual for details.
Specified Flux
indicates that the flux of the UDS at the wall will be specified.
Specified Value
indicates that the value for the UDS at the wall will be specified.
User Defined Scalar Boundary Value
contains inputs for the value of the flux of the UDS, or the value of the UDS itself, depending on your selection for that UDS under
User Defined Scalar Boundary Condition.