Inlet_Boundary_Condition

This data setup are used to define the inflow condition features. The inflow geometry is restricted to rectangular/line forms in 3D/2D configuration. In the particular case of cylindrical geometries, the inlets can be circular, annular or bowed retangular. In fact, the geometry of the inlet fits the grid topology.

Full data set of the namelist

&Inlet_Boundary_Conditions
Type_of_BC= "INLET", Direction_Normal_Plan= 1 ,
Plan_Location_Coordinate= -0.05 ,
Start_Coordinate_of_First_Span = -0.01, End_Coordinate_of_First_Span = 0.01,
Start_Coordinate_of_Second_Span= 0.0 , End_Coordinate_of_Second_Span= 0.0 ,
Flow_Direction= 1 ,
Normal_Velocity_Reference_Value= 1.5E-3 ,
Temperature_Reference_Value= 293.0 ,
Density_Reference_Value= 1.66328E-1,
Define_Velocity_profile= 0 ,
Species_Boundary_Condition_Type= 0 , Define_Mass_Fraction_profile= 0 ,
Temporal_Variation_For_Each_Species= 0 ,
Species_Reference_Value= 1.0 ,
Time_Fct_Name= "Sinus" , Time_Fct_Threshold= 0.0 ,
Time_Fct_Time_Scale= 1.0 , Time_Fct_Magnitude= 0.0 ,
End_of_Data_Block= .true. /

Whatever the grid topology, the orientation and the span of the inflow are defined by means of : the normal vector of the inlet plane associated to a specific direction (I,J or K). the coordinates associated to the position of the inlet sides along the two perpendicular directions to the normal vector (denoted the first and second span directions). When the normal vector is oriented along the I-direction, the first span direction is J and the second is K. When the the normal vector is oriented along the J-direction, the first span direction is I and the second is K. When the the normal vector is oriented along the K-direction, the first span direction is I and the second is J. When the inflow conditions are constant the time data can be omitted. Don't forget to set the boolean data “End_of_Data_Block” at the end of the namelist. A “.true.” value means the end of the data block when several namelists are used to create several inlets. Find some examples here .

Definition of the data set

Type_of_BC

Type : String of 6 characters

Name to define the inflow boundary conditions type. Only one kind of inlet boundary condition is defined at present (Dirichlet type) and the associated name is “INLET”.

Direction_Normal_Plan

Type : integer value

This data defines the orientation of the normal vector the inlet in respect with the grid {I,J,K}. The values 1, 2 or 3 point the I, J or K-direction, respectively.

Default value : none

Plan_Location_Coordinate

Type: real value

Coordinate of the position of the inlet plan along the normal direction previously defined.

Default value : none

Start_Coordinate_of_First_Span

Type : real value

This coordinate defines the lower side of the inlet plan span along “the first direction” (see the note above).

Default value : none

End_Coordinate_of_First_Span

Type : real value

This coordinate defines the upper side of the inlet plan span along “the first direction” (see the note above).

Start_Coordinate_of_Second_Span

Type : real value

This coordinate defines the lower side of the inlet plan span along “the second direction” (see the note above).

Default value : none

End_Coordinate_of_Second_Span

Type : real value

This coordinate defines the upper side of the inlet plan span along “the second direction” (see the note above).

Default value : none

Flow_Direction

Type : integer value

This value is set to 1 or -1. It indicates the presumed direction of the inflow in accordance to the position of the outlet. If the inflow is oriented along the increasing or decreasing index (for a given direction) the value is set to 1 or -1, respectively.

Default value : none

Normal_Velocity_Reference_Value

Type : real value

Reference value of the normal component of the velocity. The other ones are automatically set to zero.

Default value : none

Define_Velocity_profile

Type : Integer value

Type of the velocity profile over the inlet :

0 : Uniform profile

1 : Parabolic profile along the first span direction (the mean velocity at the inlet is defined with the “Normal_Velocity_Reference_Value”)

2 : Parabolic profile along the second span direction (the mean velocity at the inlet is defined with the “Normal_Velocity_Reference_Value”)

Default value : none

Variable_Flowrate

Type : Integer value

This data allows the user to define a time variation of the flowrate :

0 : the flowrate is constant

1 : the flowrate is variable in time. The time functions can be defined by the users in the specific module of the code named “module_user_defined_temporal_function.f90”. The parameters of the time-function can be read from the following variables :

Time_Fct_Name :character string bounded to the user's time function defined in the module “module_user_define_temporal_function.f90”. At present, two temporal functions are available, The sinusoidal function (named “Sinus”) and the linear-ramp function, (called “ Linear_Ramp”).

Time_Fct_Threshold : time from which the time function starts.

Time_Fct_Time_Scale : time scale of the function (i.e the period for the sinusoidal function, and the time range for the linear ramp function)

Time_Fct_Magnitude : magnitude of the time function.

Default value= 0

Temperature_Reference_Value

Type : real value

Reference value of the temperature.

Default value : none

Density_Reference_Value

Type : real value

Reference value of the fluid density.

Species_Reference_Value

Type : array of real values (the size is determined by the species number considered)

This data setup defines the reference value of mass fractions for each species

Default value : none

Species_Boundary_Condition_Type

Type : integer value

This option defines the inlet boundary

condition type for the density of species

0 : Dirichlet condition (the mass fraction value is imposed at the center of the ghost-cell).

1 : The mass flux value is imposed on the inlet plan. This flux is defined as the product of the variables “Define_Velocity_profile”, “Normal_Velocity_Reference_Value” and “Species_Reference_Value” (Rho.U.Yi).

Default value : none

Define_Mass_Fraction_profile

Type : integer value

This data determines the distribution law on the first species mass fraction over the inlet (the complementary law is reported on the 2nd species by default):

0 : Uniform profile

1 : Heaviside profile centered on the inlet

Default value : none

Temporal_Variation_For_Each_Species

Type : array of integer value (the size is determined by the species number considered)

This data setup defines time function used to define the temporal variation of species. The time functions can be programmed by the user in the fortran file named “module_user_define_temporal_functions.f90”. Sinusoidal and linear ramp functions can be used by means of time parameters already described in the part “Variable_Flowrate” .

Default value : none

End_of_Data_Block

Type : boolean value

Specify the end of the namelist or a group of this type of namelist (if true).