openswmm::transport::fvkernels Namespace Reference

Classes
struct	NetworkMeshData
	SoA mesh geometry and topology for the FV network solver. More...
struct	NetworkStateData
	Mutable solver state — the conserved variables and the node volumes. More...
struct	SpeciesKernelView
	Non-owning view over everything the species kernels read and write. More...

Enumerations
enum class	Limiter
	Slope limiter used by the second-order (MUSCL) reconstruction. More...
enum class	ScalarScheme
	Reconstruction used for the advected scalar field. More...

Functions
void	reconstructScalars (const SpeciesKernelView &v, double dt)
void	limitSpeciesFluxes (const SpeciesKernelView &v, int species, double dt)
	Assemble the face species fluxes and limit them (Zalesak FCT).
void	dispersionSolve (const SpeciesKernelView &v, double dt)
double	limitSlope (double a, double b, Limiter lim)

Enumeration Type Documentation

Limiter

enum class openswmm::fv::Limiter : int

strong

Slope limiter used by the second-order (MUSCL) reconstruction.

ScalarScheme

enum class openswmm::fv::ScalarScheme : int

strong

Reconstruction used for the advected scalar field.

Function Documentation

dispersionSolve()

void openswmm::transport::fvkernels::dispersionSolve	(	const SpeciesKernelView &	v,
		double	dt )

Implicit longitudinal dispersion (decision D-FV1): one Thomas tridiagonal solve per cell chain per species; unconditionally stable, removes the Δx²/(2·D_L) explicit constraint. E3: honours v.cell_dispersion when set (per-conduit / FISCHER coefficients); scalar v.dispersion otherwise.

Cell coefficient under either model. E3 bitwise-preservation note: each face uses 0.5*(D_i + D_j). With cd == nullptr both operands are v.dispersion, and 0.5*(D + D) == D EXACTLY in binary floating point (the ×2 and ×0.5 are exponent shifts), so the face coefficient — and therefore every downstream product in the same evaluation order — is bit-identical to the pre-E3 v.dispersion * … expression. The FV solver passes cd == nullptr and keeps its bitwise contract (E0 gate).

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limitSlope()

double openswmm::transport::fvkernels::limitSlope ( double a, double b, Limiter lim )

inline

Slope limiters for the second-order scalar reconstruction. All three are TVD; superbee is the sharpest and can artificially steepen smooth profiles, minmod the most diffusive and most robust. (Moved verbatim from ExplicitFvSolver.cpp; also used by the solver's hydrodynamic reconstructState.)

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limitSpeciesFluxes()

void openswmm::transport::fvkernels::limitSpeciesFluxes	(	const SpeciesKernelView &	v,
		int	species,
		double	dt )

Assemble the face species fluxes and limit them (Zalesak FCT).

Bracketing the reconstructed FACE value between its two cells is necessary but NOT sufficient for the discrete maximum principle: under reversing, unsteady flow with the cell areas evolving underneath the scalar, a face value legitimately inside its bracket can still drain more solute than its donor cell holds. Measured: QUICKEST-ULTIMATE produced −1.3e-3 on a step-function advection case with wall reflections, which is not acceptable in a water-quality model.

The fix has to limit the FLUX, not the result. Clipping the updated concentration would enforce the bound but destroy exact solute conservation (§6.11c) — the two properties trade off, and Zalesak (1979) is the construction that keeps both: blend each face's high-order flux back toward first-order upwind by the largest factor that no incident cell's bound rejects. The SAME limited flux updates both incident cells, so conservation is untouched.

Assemble the face species fluxes and limit them (Zalesak FCT). See the implementation notes: limits the FLUX, not the result, so the discrete maximum principle and exact solute conservation hold together.

The flux record with the positivity-scaled mass flux substituted in, so the species rides on exactly the water the hydrodynamic update moved. (Formerly ExplicitFvSolver::adjustedFlux.)

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reconstructScalars()

void openswmm::transport::fvkernels::reconstructScalars	(	const SpeciesKernelView &	v,
		double	dt )

Scalar reconstruction — the anti-diffusion layer (FV plan §3.2). Computes limited face values for every species and calls limitSpeciesFluxes to assemble/limit the face species fluxes into f_phi_flux.

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