mod_flow_fields Module

Allocation and management of primary flow variables and projection fluxes.

This module is the central owner of hydrodynamic state used by the fractional-step solver. Arrays are globally sized because every MPI rank stores the replicated mesh, but numerical kernels update only owned cells or owner-owned faces before halo exchange.

Important flux convention: fields%face_flux(f) is the volumetric face flux $u_f \cdot n_f A_f$ in $\mathrm{m^3/s}$, oriented from mesh%faces(f)%owner to mesh%faces(f)%neighbor. Cell-local loops reorient it to outward-from-cell by changing the sign when the current cell is the neighbor. fields%mass_flux(f) has the same owner-to-neighbor orientation and stores $\rho_f u_f \cdot n_f A_f$ in $\mathrm{kg/s}$.

Constant-density mode targets $\nabla \cdot u = 0$. Guarded variable-density low-Mach mode targets $\nabla \cdot u = S$, where fields%projection_divergence_source records the source actually consumed by the most recent projection and fields%divergence_source may later be advanced by energy/thermo density updates for the next projection.

Derived Types

type, public ::  flow_fields_t

Container for all primary hydrodynamic fields.

Components

Type	Visibility	Attributes		Name		Initial
real(kind=rk),	public,	allocatable	::	div(:)
real(kind=rk),	public,	allocatable	::	divergence_source(:)			Current low-Mach divergence source $S$ [1/s] prepared for the next projection. Read more…
real(kind=rk),	public,	allocatable	::	face_flux(:)			Conservative face-centered volumetric flux $U_f = \mathbf{u}_f \cdot \mathbf{n}_f A_f$. Oriented according to the face normal (owner $\rightarrow$ neighbor).
real(kind=rk),	public,	allocatable	::	mass_flux(:)			Conservative face-centered mass flux $\dot{m}_f = \rho_f U_f$. Oriented according to the face normal (owner $\rightarrow$ neighbor).
real(kind=rk),	public,	allocatable	::	p(:)
real(kind=rk),	public,	allocatable	::	phi(:)
real(kind=rk),	public,	allocatable	::	projection_divergence_source(:)			Copy of the low-Mach divergence source actually consumed by the latest projection. This distinguishes the projection residual div(u)-S_projection from post-energy source-evolution diagnostics using divergence_source.
real(kind=rk),	public,	allocatable	::	projection_rho(:)
real(kind=rk),	public,	allocatable	::	rhs_old(:,:)			Storage for the previous explicit RHS (Advection + Diffusion). Required for 2nd-order Adams-Bashforth (AB2) time marching.
logical,	public		::	rhs_old_valid	=	.false.
real(kind=rk),	public,	allocatable	::	u(:,:)
real(kind=rk),	public,	allocatable	::	u_old(:,:)
real(kind=rk),	public,	allocatable	::	u_star(:,:)

Subroutines

public subroutine allocate_fields(mesh, fields)

Dynamically allocates all arrays within the flow fields container.

Read more…

Arguments

Type	Intent	Optional	Attributes		Name
type(mesh_t),	intent(in)			::	mesh	The mesh structure defining the domain size.
type(flow_fields_t),	intent(inout)			::	fields	The container to be allocated.

public subroutine finalize_fields(fields)

Deallocates all arrays and resets validity flags.

Arguments

Type	Intent	Optional	Attributes		Name
type(flow_fields_t),	intent(inout)			::	fields	The container to be cleared.

public subroutine initialize_fields(mesh, fields)

Initializes flow fields and sets simulation initial conditions.

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Arguments

Type	Intent	Optional	Attributes		Name
type(mesh_t),	intent(in)			::	mesh	The computational mesh.
type(flow_fields_t),	intent(inout)			::	fields	The fields container to initialize.