openswmm::twoD::swe Namespace Reference

Classes
struct	FaceFlux
struct	FaceSide

Functions
OPENSWMM_KERNEL_FN void	physicalFlux (const FaceSide &s, double &fh, double &fn, double &ft) noexcept
	Physical flux of the SWE in the normal frame: [h·un, h·un² + ½g h², h·un·ut].
OPENSWMM_KERNEL_FN void	waveSpeeds (const FaceSide &L, const FaceSide &R, double &sl, double &sr) noexcept
	Wave-speed estimates S_L ≤ S_R (Toro 2001 §10.4): two-rarefaction estimate for wet–wet faces, the exact dry-bed front speeds otherwise.
OPENSWMM_KERNEL_FN void	hllcFlux (const FaceSide &L, const FaceSide &R, double &fh, double &fn, double &ft, double &sstar) noexcept
	HLLC flux in the face-normal frame.
OPENSWMM_KERNEL_FN bool	faceFlux (double etaL, double hL, double qxL, double qyL, double etaR, double hR, double qxR, double qyR, double nx, double ny, double h_dry, FaceFlux &out, double &corrL_x, double &corrL_y, double &corrR_x, double &corrR_y) noexcept
	Full face evaluation: hydrostatic reconstruction, rotation, HLLC, rotation back, and the per-side bed-slope corrections.
OPENSWMM_KERNEL_FN bool	faceFluxReconBed (double etaLf, double uxLf, double uyLf, double zL, double hL_cell, double etaRf, double uxRf, double uyRf, double zR, double hR_cell, double nx, double ny, double h_dry, FaceFlux &out, double &corrL_x, double &corrL_y, double &corrR_x, double &corrR_y, double zLf, double zRf) noexcept
	Second-order face flux with independently reconstructed depth/bed.
OPENSWMM_KERNEL_FN bool	faceFluxRecon (double etaLf, double uxLf, double uyLf, double zL, double hL_cell, double etaRf, double uxRf, double uyRf, double zR, double hR_cell, double nx, double ny, double h_dry, FaceFlux &out, double &corrL_x, double &corrL_y, double &corrR_x, double &corrR_y) noexcept
	Piecewise-constant-bed compatibility entry point.
OPENSWMM_KERNEL_FN double	bjLimiter (double w, double wf, double wmin, double wmax) noexcept
	Barth–Jespersen limiter factor φ ∈ [0, 1] for one cell/variable given the cell value w, the extrapolated face value wf and the min/max over the cell and its neighbours.
OPENSWMM_KERNEL_FN void	frictionUpdate (double &qx, double &qy, double h, double n, double dt) noexcept
	Semi-implicit Manning friction on a cell's unit discharge over Δt: q⃗ ← q⃗ / (1 + g·Δt·n²·|q⃗| / h^{7/3}). Only shrinks |q⃗|; never reverses it.
OPENSWMM_KERNEL_FN double	criticalDepth (double q) noexcept
	Critical depth for a per-metre discharge q: (q²/g)^{1/3} — the ghost depth of a prescribed-flow boundary entering a dry cell.
OPENSWMM_KERNEL_FN double	depthFromInvariantAndDischarge (double r, double q, double h_interior) noexcept
	Ghost depth of a SUBCRITICAL prescribed-discharge boundary.

Variables
constexpr double	kGravity = 9.80665

Function Documentation

bjLimiter()

OPENSWMM_KERNEL_FN double openswmm::twoD::swe::bjLimiter ( double w, double wf, double wmin, double wmax )

noexcept

Barth–Jespersen limiter factor φ ∈ [0, 1] for one cell/variable given the cell value w, the extrapolated face value wf and the min/max over the cell and its neighbours.

Parameters

[in]	w	Finite cell-centered variable in the variable's own units.
[in]	wf	Finite unlimited extrapolated face value in the same units.
[in]	wmin	Minimum over the cell and neighbors; must satisfy wmin <= w.
[in]	wmax	Maximum over the cell and neighbors; must satisfy w <= wmax.

Returns

Dimensionless limiter in [0,1] when the extrema bracket w; one when |wf-w| <= 1e-14. The kernel does not clamp invalid negative ratios.

Note

Pure host/device arithmetic: no allocation, exceptions, retained pointers or model state mutation. Caller supplies finite valid physical inputs; no general validation.

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criticalDepth()

OPENSWMM_KERNEL_FN double openswmm::twoD::swe::criticalDepth ( double q )

noexcept

Critical depth for a per-metre discharge q: (q²/g)^{1/3} — the ghost depth of a prescribed-flow boundary entering a dry cell.

Parameters

[in]

q

Finite signed unit-width discharge, m2/s; sign is squared.

Returns

Nonnegative critical water depth, m; direct q*q requires caller-bounded magnitude.

Note

Pure host/device arithmetic: no allocation, exceptions, retained pointers or model state mutation. Caller supplies finite valid physical inputs; no general validation.

depthFromInvariantAndDischarge()

OPENSWMM_KERNEL_FN double openswmm::twoD::swe::depthFromInvariantAndDischarge ( double r, double q, double h_interior )

noexcept

Ghost depth of a SUBCRITICAL prescribed-discharge boundary.

One characteristic leaves the domain there, so its Riemann invariant r = u + 2c is carried out from the interior and, with the prescribed per-metre discharge q = u·h, fixes the boundary depth:

q/h + 2·sqrt(g·h) = r      ⇔      2·sqrt(g)·s³ − r·s² + q = 0,  s = sqrt(h)

Newton on s from the interior depth with positive/finite-step guards (≤ 40 iterations); returns h_interior when it cannot converge — the caller's mass flux is prescribed either way, so a fallback only costs accuracy in the momentum flux, never conservation. Signs follow the outward normal: an inflow has q < 0.

Parameters

[in]	r	Finite outgoing normal Riemann invariant u+2*sqrt(g*h), m/s.
[in]	q	Finite prescribed normal unit-width discharge, m2/s; outward-positive, inflow negative.
[in]	h_interior	Finite nonnegative interior depth/fallback, m.

Returns

Positive ghost depth in m when a physical Newton root passes convergence checks, otherwise h_interior.

Note

At most 40 Newton iterations with positive-step/finite-derivative guards, not a bracketed root solve. Nonpositive interior depth starts the iteration at 1e-6 m. Pure host/device computation; no separate failure code or retained state.

faceFlux()

OPENSWMM_KERNEL_FN bool openswmm::twoD::swe::faceFlux ( double etaL, double hL, double qxL, double qyL, double etaR, double hR, double qxR, double qyR, double nx, double ny, double h_dry, FaceFlux & out, double & corrL_x, double & corrL_y, double & corrR_x, double & corrR_y )

noexcept

Full face evaluation: hydrostatic reconstruction, rotation, HLLC, rotation back, and the per-side bed-slope corrections.

Returns

true when the face carries flux OR a bed-pressure correction. A blocked wet/dry face still supplies the wet cell's wall pressure. false ⇒ every output is zero.

Parameters

[in]	etaL	Finite left cell free surface, m.
[in]	hL	Finite nonnegative left mean depth, m.
[in]	qxL	Finite left X unit-width discharge, m2/s.
[in]	qyL	Finite left Y unit-width discharge, m2/s.
[in]	etaR	Finite right cell free surface, m.
[in]	hR	Finite nonnegative right mean depth, m.
[in]	qxR	Finite right X unit-width discharge, m2/s.
[in]	qyR	Finite right Y unit-width discharge, m2/s.
[in]	nx	Finite X component of a unit normal directed left-to-right.
[in]	ny	Finite Y component of the same normal.
[in]	h_dry	Finite nonnegative depth threshold in m for shoreline velocity suppression.
[out]	out	Completely assigned Cartesian FaceFlux: mass m2/s, momentum m3/s2, sstar m/s.
[out]	corrL_x	Left-side X bed-source correction, m3/s2 per unit face length.
[out]	corrL_y	Left-side Y bed-source correction in the same units.
[out]	corrR_x	Right-side X bed-source correction with opposite outward normal, m3/s2.
[out]	corrR_y	Right-side Y bed-source correction, m3/s2.

Returns

True for a face flux or nonzero bed-pressure correction; false only when every output is zero.

Note

All outputs are assigned; keep outputs distinct and independent of input fields. Pure host/device function; no validation, ownership transfer, allocation or timestep update. Multiply momentum/source terms by face length and dt in the caller.

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faceFluxRecon()

OPENSWMM_KERNEL_FN bool openswmm::twoD::swe::faceFluxRecon ( double etaLf, double uxLf, double uyLf, double zL, double hL_cell, double etaRf, double uxRf, double uyRf, double zR, double hR_cell, double nx, double ny, double h_dry, FaceFlux & out, double & corrL_x, double & corrL_y, double & corrR_x, double & corrR_y )

noexcept

Piecewise-constant-bed compatibility entry point.

Parameters

[in]	etaLf	Finite reconstructed left face free surface, m.
[in]	uxLf	Finite reconstructed left X velocity, m/s.
[in]	uyLf	Finite reconstructed left Y velocity, m/s.
[in]	zL	Finite left cell-equivalent bed elevation, m.
[in]	hL_cell	Finite nonnegative left cell mean depth, m.
[in]	etaRf	Finite reconstructed right face free surface, m.
[in]	uxRf	Finite reconstructed right X velocity, m/s.
[in]	uyRf	Finite reconstructed right Y velocity, m/s.
[in]	zR	Finite right cell-equivalent bed elevation, m.
[in]	hR_cell	Finite nonnegative right cell mean depth, m.
[in]	nx	Finite X component of a unit normal directed left-to-right.
[in]	ny	Finite Y component of the same normal.
[in]	h_dry	Finite nonnegative depth threshold in m for shoreline velocity suppression.
[out]	out	Completely assigned Cartesian FaceFlux: mass m2/s, momentum m3/s2, sstar m/s.
[out]	corrL_x	Left-side X bed-source correction, m3/s2 per unit face length.
[out]	corrL_y	Left-side Y bed-source correction in the same units.
[out]	corrR_x	Right-side X bed-source correction with opposite outward normal, m3/s2.
[out]	corrR_y	Right-side Y bed-source correction, m3/s2.

Returns

True for a face flux or nonzero bed-pressure correction; false only when every output is zero.

Note

All outputs are assigned; keep outputs distinct and independent of input fields. Pure host/device function; no validation, ownership transfer, allocation or timestep update. Multiply momentum/source terms by face length and dt in the caller. This compatibility wrapper uses cell beds as face beds.

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faceFluxReconBed()

OPENSWMM_KERNEL_FN bool openswmm::twoD::swe::faceFluxReconBed ( double etaLf, double uxLf, double uyLf, double zL, double hL_cell, double etaRf, double uxRf, double uyRf, double zR, double hR_cell, double nx, double ny, double h_dry, FaceFlux & out, double & corrL_x, double & corrL_y, double & corrR_x, double & corrR_y, double zLf, double zRf )

noexcept

Second-order face flux with independently reconstructed depth/bed.

zLf/zRf are face beds from the limited eta and depth reconstruction; zL/zR are the cell-equivalent beds. Add the hydrostatic face correction and the centered bed contribution -g*(h_cell+h_face)/2*(z_face-z_cell). The latter integrates a linear depth along the cell-to-face bed segment. For constant eta this reduces to g/2*(h_star^2-h_cell^2), preserving lake-at-rest balance even next to a first-order cell. On a flat bed the within-cell contribution vanishes. Face-depth positivity and cell-centered shoreline velocity are enforced by computeLimitedGradientsSwe().

Parameters

[in]	etaLf	Finite reconstructed left face free surface, m.
[in]	uxLf	Finite reconstructed left X velocity, m/s.
[in]	uyLf	Finite reconstructed left Y velocity, m/s.
[in]	zL	Finite left cell-equivalent bed elevation, m.
[in]	hL_cell	Finite nonnegative left cell mean depth, m.
[in]	etaRf	Finite reconstructed right face free surface, m.
[in]	uxRf	Finite reconstructed right X velocity, m/s.
[in]	uyRf	Finite reconstructed right Y velocity, m/s.
[in]	zR	Finite right cell-equivalent bed elevation, m.
[in]	hR_cell	Finite nonnegative right cell mean depth, m.
[in]	nx	Finite X component of a unit normal directed left-to-right.
[in]	ny	Finite Y component of the same normal.
[in]	h_dry	Finite nonnegative depth threshold in m for shoreline velocity suppression.
[out]	out	Completely assigned Cartesian FaceFlux: mass m2/s, momentum m3/s2, sstar m/s.
[out]	corrL_x	Left-side X bed-source correction, m3/s2 per unit face length.
[out]	corrL_y	Left-side Y bed-source correction in the same units.
[out]	corrR_x	Right-side X bed-source correction with opposite outward normal, m3/s2.
[out]	corrR_y	Right-side Y bed-source correction, m3/s2.
[in]	zLf	Finite reconstructed left face bed elevation, m.
[in]	zRf	Finite reconstructed right face bed elevation, m.

Returns

True for a face flux or nonzero bed-pressure correction; false only when every output is zero.

Note

All outputs are assigned; keep outputs distinct and independent of input fields. Pure host/device function; no validation, ownership transfer, allocation or timestep update. Multiply momentum/source terms by face length and dt in the caller.

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frictionUpdate()

OPENSWMM_KERNEL_FN void openswmm::twoD::swe::frictionUpdate ( double & qx, double & qy, double h, double n, double dt )

noexcept

Semi-implicit Manning friction on a cell's unit discharge over Δt: q⃗ ← q⃗ / (1 + g·Δt·n²·|q⃗| / h^{7/3}). Only shrinks |q⃗|; never reverses it.

Parameters

[in,out]	qx	X unit-width discharge, m2/s.
[in,out]	qy	Y unit-width discharge, m2/s; distinct from qx.
[in]	h	Finite cell mean depth, m; nonpositive zeros both discharges.
[in]	n	Finite nonnegative Manning roughness, s/m^(1/3).
[in]	dt	Finite nonnegative update duration, s.

Note

In-place pure host/device scalar update; semi-implicit denominator preserves direction for valid inputs. No allocation, ledger update, or other model-state mutation.

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hllcFlux()

OPENSWMM_KERNEL_FN void openswmm::twoD::swe::hllcFlux ( const FaceSide & L, const FaceSide & R, double & fh, double & fn, double & ft, double & sstar )

noexcept

HLLC flux in the face-normal frame.

Parameters

[in]	L	Borrowed finite reconstructed face state: nonnegative h in m and normal/tangential velocities in m/s.
[in]	R	Borrowed finite reconstructed face state: nonnegative h in m and normal/tangential velocities in m/s.
[out]	fh	Mass flux in m2/s, positive left-to-right.
[out]	fn	Normal momentum flux in m3/s2.
[out]	ft	Tangential momentum flux in m3/s2.
[out]	sstar	Contact-wave speed in m/s for passive-scalar donor selection.

Note

All outputs are assigned, including zero for both-dry faces; degenerate contact denominator falls back to mean normal velocity. Distinct outputs and finite nonnegative depths are required. No allocation or model-state mutation.

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physicalFlux()

OPENSWMM_KERNEL_FN void openswmm::twoD::swe::physicalFlux ( const FaceSide & s, double & fh, double & fn, double & ft )

noexcept

Physical flux of the SWE in the normal frame: [h·un, h·un² + ½g h², h·un·ut].

Parameters

[in]	s	Borrowed finite reconstructed face state: nonnegative h in m and normal/tangential velocities in m/s.
[out]	fh	Mass/unit-width volume flux in m2/s.
[out]	fn	Normal momentum flux in m3/s2.
[out]	ft	Tangential momentum flux in m3/s2.

Note

Pure scalar host/device evaluation; outputs must be distinct and must not alias input fields. No validation, allocation or state mutation.

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waveSpeeds()

OPENSWMM_KERNEL_FN void openswmm::twoD::swe::waveSpeeds ( const FaceSide & L, const FaceSide & R, double & sl, double & sr )

noexcept

Wave-speed estimates S_L ≤ S_R (Toro 2001 §10.4): two-rarefaction estimate for wet–wet faces, the exact dry-bed front speeds otherwise.

Parameters

[in]	L	Borrowed finite reconstructed face state: nonnegative h in m and normal/tangential velocities in m/s.
[in]	R	Borrowed finite reconstructed face state: nonnegative h in m and normal/tangential velocities in m/s.
[out]	sl	Estimated leftmost wave speed, m/s.
[out]	sr	Estimated rightmost wave speed, m/s.

Note

Both-dry faces return zero speeds. Caller supplies distinct output scalars and valid finite depths; no allocation, mutation or robust-predicate error status.

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Variable Documentation

kGravity

double openswmm::twoD::swe::kGravity = 9.80665

inlineconstexpr