Boundary Block

The boundary block defines the boundary conditions for the computational domain. It specifies the type of boundary on each side, whether reverse flows are allowed, special inlet velocity settings, and the reference atmospheric pressure.

Warning

This block is mandatory for all simulations.

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Flags Overview

Note

All flags and their description are included in the table below. A detailed description of which values are possible for each input flag follows.

Flag	Required	Description
BC_LEFT	Yes	defines the boundary condition on the left side of the computational domain (list in DINO_IN)
BD_RIGHT	Yes	defines the boundary condition on the right side of the computational domain (list in DINO_IN)
NO_REVERSE_FLOW_X	No	disables reverse flow in x direction
BC_UP	Yes	defines the boundary condition on the upper side of the computational domain (list in DINO_IN)
BD_DOWN	Yes	defines the boundary condition on the bottom side of the computational domain (list in DINO_IN)
NO_REVERSE_FLOW_Y	No	disables reverse flow in y direction
BC_FRONT	Yes	defines the boundary condition on the front side of the computational domain (list in DINO_IN)
BC_BACK	Yes	defines the boundary condition on the back side of the computational domain (list in DINO_IN)
NO_REVERSE_FLOW_Z	No	disables reverse flow in z direction
BC_VEL_INLET	No	indicates that the inlet velocity is not constant and defined by the user
ADD_SPONGE_LAYER	No	allows to add a sponge layer in x, y, and/or z direction
U_IN_CTRL	No	controls the x velocity during flame speed computation works only for 1D simulation
U_IN_CTRL_3D	No	controls the x velocity during flame speed computation works for 2D or 3D simulation
DPDT_TH_ON	No	enables considering dp/dt in the temperature equation
P_INFTY	Yes	defines the atmospheric pressure

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Flags Details

BC_LEFT

• Type: integer
• Values: 0–10
• Default: 1
• Description: defines the boundary condition on the left side of the computational domain (list in DINO_IN)

BC_RIGHT

• Type: integer
• Values: 0–10
• Default: 2
• Description: defines the boundary condition on the right side of the computational domain (list in DINO_IN)

NO_REVERSE_FLOW_X

• Type: boolean
• Values: .TRUE./.FALSE.
• Default: .FALSE.
• Description: disables reverse flow in x direction

BC_UP

• Type: integer
• Values: 0–10
• Default: 3
• Description: defines the boundary condition on the upper side of the computational domain (list in DINO_IN)

BC_DOWN

• Type: integer
• Values: 0–10
• Default: 3
• Description: defines the boundary condition on the bottom side of the computational domain (list in DINO_IN)

NO_REVERSE_FLOW_Y

• Type: boolean
• Values: .TRUE./.FALSE.
• Default: .FALSE.
• Description: disables reverse flow in y direction

BC_FRONT

• Type: integer
• Values: 0–10
• Default: 3
• Description: defines the boundary condition on the front side of the computational domain (list in DINO_IN)

BC_BACK

• Type: integer
• Values: 0–10
• Default: 3
• Description: defines the boundary condition on the back side of the computational domain (list in DINO_IN)

NO_REVERSE_FLOW_Z

• Type: boolean
• Values: .TRUE./.FALSE.
• Default: .FALSE.
• Description: disables reverse flow in z direction

BC_VEL_INLET

• Type: boolean
• Values: .TRUE./.FALSE.
• Default: .FALSE.
• Description: indicates that the inlet velocity is not constant and defined by the user

ADD_SPONGE_LAYER

• Type: boolean array with three entries, one entry for each direction
• Values: .TRUE./.FALSE., .TRUE./.FALSE., .TRUE./.FALSE.
• Default: .false., .false., .false.
• Description: allows to add sponge layer in x, y, and/or z direction

U_IN_CTRL

• Type: boolean
• Values: .TRUE./.FALSE.
• Default: .FALSE.
• Description: controls the x velocity during flame speed computation in 1D simulation

U_IN_CTRL_3D

• Type: boolean
• Values: .TRUE./.FALSE.
• Default: .FALSE.
• Description: controls the x velocity during flame speed computation in 2D or 3D simulation

DPDT_TH_ON

• Type: boolean
• Values: .TRUE./.FALSE.
• Default: .FALSE.
• Description: enables considering dp/dt in the temperature equation

P_INFTY

• Type: real
• Values: positive real
• Default: 101325 Pa
• Description: defines the atmospheric pressure

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Example:

&NML_BOUNDARY
    BC_LEFT=1,
    BC_RIGHT=2,
    NO_REVERSE_FLOW_X=.FALSE.,
    BC_UP=3,
    BC_DOWN=3,
    NO_REVERSE_FLOW_Y=.FALSE.,
    BC_FRONT=3,
    BC_BACK=3,
    NO_REVERSE_FLOW_Z=.FALSE.,
    BC_VEL_INLET=.false.,
    ADD_SPONGE_LAYER=.FALSE., .false., .FALSE.,
    U_IN_CTRL=.FALSE.,
    U_IN_CTRL_3D=.FALSE.,
    DPDT_TH_ON=.FALSE.,
    P_INFTY=101325.D0, 
/