mod_bc Module

Boundary condition (BC) management, parsing, and physical evaluation.

This module provides the infrastructure to map user-defined case configuration (case.nml) to the geometric patches of the mesh. It handles the storage of boundary data (velocity, pressure, species) and provides low-level evaluation routines used by the spatial operators (e.g., flux calculation, gradient evaluation).

Supported BC Types: 1. bc_wall: No-slip/No-penetration condition. - Velocity is set to the specified wall velocity (default zero). - Pressure gradient is zero (Neumann). 2. bc_symmetry: Zero-gradient for parallel components, zero for normal. - Enforces no-flow across the boundary while allowing slip. 3. bc_periodic: Topology-linked faces for repeating domains. - Requires a valid periodic.dat file created by the mesh converter. 4. bc_dirichlet: Fixed value (Inlet). - Explicitly sets the field value at the face. 5. bc_neumann: Fixed gradient (Zero-Gradient Outlet). - Sets the face value equal to the adjacent interior cell value.


Uses

  • module~~mod_bc~~UsesGraph module~mod_bc mod_bc module~mod_input mod_input module~mod_bc->module~mod_input module~mod_kinds mod_kinds module~mod_bc->module~mod_kinds module~mod_mesh_types mod_mesh_types module~mod_bc->module~mod_mesh_types module~mod_input->module~mod_kinds iso_fortran_env iso_fortran_env module~mod_kinds->iso_fortran_env module~mod_mesh_types->module~mod_kinds

Used by

  • module~~mod_bc~~UsedByGraph module~mod_bc mod_bc module~mod_energy mod_energy module~mod_energy->module~mod_bc module~mod_fields mod_fields module~mod_energy->module~mod_fields module~mod_fields->module~mod_bc module~mod_flow_projection mod_flow_projection module~mod_flow_projection->module~mod_bc module~mod_flow_projection->module~mod_fields module~mod_species mod_species module~mod_species->module~mod_bc module~mod_species->module~mod_fields module~mod_species->module~mod_flow_projection program~lowmach_react_hex lowmach_react_hex program~lowmach_react_hex->module~mod_bc program~lowmach_react_hex->module~mod_energy program~lowmach_react_hex->module~mod_fields program~lowmach_react_hex->module~mod_flow_projection program~lowmach_react_hex->module~mod_species module~mod_output mod_output program~lowmach_react_hex->module~mod_output module~mod_output->module~mod_energy module~mod_output->module~mod_fields module~mod_output->module~mod_flow_projection module~mod_output->module~mod_species

Variables

Type Visibility Attributes Name Initial
integer, public, parameter :: bc_dirichlet = 4
integer, public, parameter :: bc_neumann = 5
integer, public, parameter :: bc_periodic = 3
integer, public, parameter :: bc_symmetry = 2
integer, public, parameter :: bc_unknown = 0
integer, public, parameter :: bc_wall = 1

Derived Types

type, public ::  bc_patch_t

Container for boundary data assigned to a specific mesh patch.

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Components

Type Visibility Attributes Name Initial
real(kind=rk), public :: dpdn = zero
character(len=name_len), public :: name = ""
integer, public :: patch_id = 0
real(kind=rk), public :: pressure = zero
integer, public :: pressure_type_id = bc_unknown
real(kind=rk), public :: species_Y(max_species) = zero
integer, public :: species_type_id = bc_unknown

Species boundary settings.
real(kind=rk), public :: temperature = 300.0_rk
integer, public :: temperature_type_id = bc_unknown

Temperature/enthalpy boundary settings.
integer, public :: type_id = bc_unknown
character(len=name_len), public :: type_name = ""
real(kind=rk), public :: velocity(3) = zero
integer, public :: velocity_type_id = bc_unknown

Field-specific overrides.

type, public ::  bc_set_t

Global set of boundary conditions covering all mesh patches.

Components

Type Visibility Attributes Name Initial
integer, public :: npatches = 0
type(bc_patch_t), public, allocatable :: patches(:)

Functions

public function boundary_pressure_type(mesh, bc, face_id) result(type_id)

Arguments

Type IntentOptional Attributes Name
type(mesh_t), intent(in) :: mesh
type(bc_set_t), intent(in) :: bc
integer, intent(in) :: face_id

Return Value integer

public function face_effective_neighbor(mesh, bc, face_id, cell_id) result(neighbor)

Returns the neighbor cell index, accounting for periodic connectivity.

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Arguments

Type IntentOptional Attributes Name
type(mesh_t), intent(in) :: mesh

The computational mesh.
type(bc_set_t), intent(in) :: bc

The active BC set.
integer, intent(in) :: face_id

Global index of the face.
integer, intent(in) :: cell_id

Index of the cell requesting the neighbor.

Return Value integer

public function is_periodic_face(mesh, bc, face_id)

Returns true if the face belongs to a periodic boundary.

Arguments

Type IntentOptional Attributes Name
type(mesh_t), intent(in) :: mesh
type(bc_set_t), intent(in) :: bc
integer, intent(in) :: face_id

Return Value logical

public function patch_type_for_face(mesh, bc, face_id) result(type_id)

Retrieves the master BC type for a given face ID.

Arguments

Type IntentOptional Attributes Name
type(mesh_t), intent(in) :: mesh

The computational mesh.
type(bc_set_t), intent(in) :: bc

The active BC set.
integer, intent(in) :: face_id

Global index of the face.

Return Value integer

private function parse_bc_type(text) result(type_id)

Converts a case-insensitive string to its corresponding internal BC type ID.

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Arguments

Type IntentOptional Attributes Name
character(len=*), intent(in) :: text

String representation (e.g., "Wall", "Periodic", "Dirichlet").

Return Value integer


Subroutines

public subroutine boundary_pressure(mesh, bc, face_id, interior_p, ext_p, is_dirichlet)

Evaluates pressure at a boundary face.

Arguments

Type IntentOptional Attributes Name
type(mesh_t), intent(in) :: mesh
type(bc_set_t), intent(in) :: bc
integer, intent(in) :: face_id
real(kind=rk), intent(in) :: interior_p
real(kind=rk), intent(out) :: ext_p
logical, intent(out) :: is_dirichlet

public subroutine boundary_species(mesh, bc, face_id, k, interior_Y, ext_Y, is_dirichlet)

Evaluates species mass fractions at a boundary face.

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Arguments

Type IntentOptional Attributes Name
type(mesh_t), intent(in) :: mesh
type(bc_set_t), intent(in) :: bc
integer, intent(in) :: face_id
integer, intent(in) :: k
real(kind=rk), intent(in) :: interior_Y
real(kind=rk), intent(out) :: ext_Y
logical, intent(out) :: is_dirichlet

public subroutine boundary_temperature(mesh, bc, face_id, interior_T, ext_T, is_dirichlet)

Returns the pressure BC type for a given face. Evaluates temperature at a boundary face.

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Arguments

Type IntentOptional Attributes Name
type(mesh_t), intent(in) :: mesh
type(bc_set_t), intent(in) :: bc
integer, intent(in) :: face_id
real(kind=rk), intent(in) :: interior_T
real(kind=rk), intent(out) :: ext_T
logical, intent(out) :: is_dirichlet

public subroutine boundary_velocity(mesh, bc, face_id, interior_velocity, value)

Evaluates the velocity vector at a boundary face.

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Arguments

Type IntentOptional Attributes Name
type(mesh_t), intent(in) :: mesh

Mesh data structure.
type(bc_set_t), intent(in) :: bc

Boundary condition set.
integer, intent(in) :: face_id

ID of the boundary face.
real(kind=rk), intent(in) :: interior_velocity(3)
real(kind=rk), intent(out) :: value(3)

public subroutine build_bc_set(mesh, params, bc)

Synchronizes namelist parameters with mesh patches to create a complete BC set.

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Arguments

Type IntentOptional Attributes Name
type(mesh_t), intent(in) :: mesh

The computational mesh containing patch definitions.
type(case_params_t), intent(in) :: params

Parsed case configuration from case.nml.
type(bc_set_t), intent(inout) :: bc

The boundary condition set to be populated.

public subroutine finalize_bc_set(bc)

Safely deallocates the boundary condition patch array.

Arguments

Type IntentOptional Attributes Name
type(bc_set_t), intent(inout) :: bc

private subroutine ensure_periodic_links(mesh, patch_id)

Validates that periodic patches have correctly established links.

Arguments

Type IntentOptional Attributes Name
type(mesh_t), intent(in) :: mesh
integer, intent(in) :: patch_id