Declaration of scalar variables associated to species transport equations.

Variables
Variables associated to the species
integer	n_species
	Number of species.

type(species_properties), dimension(:), allocatable	species
	Species properties.

logical	species_transport_has_density_based_form = .false.
	Type of species (passive or not)

Variables associated to the time discretization
double precision	species_transport_time_step
	Current Time step.

double precision	species_transport_time_step_n
	Previous time step.

double precision	species_transport_time_step_nm1

integer	species_transport_time_order_discretization = time_order_1
	Time order discretization.

integer	species_transport_explicit_time_order_discretization = time_order_nssp32
	Time order discretization for explicit scheme.

logical	species_transport_use_explicit_terms_accumulator = .false.
	A switch for when to use explicit accumulator.

Boundary condition variables
type(t_boundary_condition), dimension(:), allocatable	species_transport_boundary_condition
	Boundary conditions.

Initializer
class(t_species_transport_ibc_initializer_item), dimension(:), allocatable	species_transport_ibc_initializer
	Immersed boundary conditions initializers.

type(t_species_initializer_set), dimension(:), allocatable	species_initializer
	Initializers.

Logical list to activate terms of the equation
logical	species_transport_has_source_term = .false.
	Has source term?

logical	species_transport_has_advection_term = .true.
	Has advection term?

logical	species_transport_has_diffusion_term = .true.
	Has diffusion term?

logical	species_transport_has_div_u_advection_term = .true.
	Has \( div(\mathbf{u}) \) advection term?

logical	species_transport_has_temporal_term = .true.
	Has temporal term?

logical	species_transport_has_linear_term = .false.
	Has linear term?

logical	species_transport_has_immersed_boundaries = .false.
	Flag to enable immersed boundaries for the energy equation.


integer, dimension(:), allocatable	species_transport_isd_target
	List of enabled immersed boundaries for the energy equation.

integer	n_ibc_concentration = 0
	Number of immersed boundaries enabled for the energy equation.

logical	species_transport_ib_has_one_sided_inner_discretization
	One sided discretization close to immersed boundaries.

integer, dimension(:), allocatable	species_transport_inner_discretization_order

Variables associated to the discretization of the advection term
integer	species_transport_diffusion_term_discretization_type = implicit_discretization
	Diffusion term discretization type (implicit or explicit)

integer	species_transport_diffusion_term_scheme = cell_centered_o2_diffusion_scheme
	Diffusion term scheme.

integer	species_transport_diffusion_explicit_time_order_discretization = time_order_1
	Diffusion term discretization (temporal discretization)

integer	species_transport_advection_term_discretization_type = implicit_discretization
	Advection term discretization type (implicit or explicit)

integer	species_transport_advection_term_scheme = cell_centered_o2_advection_scheme
	Advection term scheme.

integer	species_transport_advection_term_splitting_scheme = lie_trotter_splitting
	Advection term: Splitting Method for Lax-Wendroff TVD Superbee.

double precision, dimension(3)	species_transport_splitting_time_coeff =1d0

logical	species_transport_advection_term_dir_split = .false.
	Advection term: directional splitting option.

type(t_fv_flux), parameter	default_species_transport_advection_explicit_flux = default_flux_godunov
	Fluxes type The default explicit cell advection flux.

type(t_fv_flux)	species_transport_advection_explicit_flux = default_species_transport_advection_explicit_flux
	Fluxes type The effective explicit cell advection flux.


logical	is_species_transport_fully_explicit = .false.
	Species Transport Equations (fully explicit)

Miscellaneous variables
logical	species_transport_has_ghost_boundary_cells = .false.
	Ghost boudary cell choice.

type(t_cell_stencil)	species_transport_stencil
	Stencil.

integer	species_transport_enforced_stencil = -1
	Enforced stencil.

Linear system solver variables
type(t_ls_map)	species_transport_ls_map
	Mapping variables.

class(t_base_solver), allocatable	species_transport_solver
	Linear system solver.

Variables