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
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	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
	Face flux from RECONSTRUCTED side states (RECONSTRUCTION_ORDER 2).
OPENSWMM_KERNEL_FN double	bjLimiter (double w, double wf, double wmin, double wmax) noexcept
OPENSWMM_KERNEL_FN void	frictionUpdate (double &qx, double &qy, double h, double n, double dt) noexcept
OPENSWMM_KERNEL_FN double	criticalDepth (double q) noexcept
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.

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.

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)

Safeguarded Newton on s from the interior depth (bracketed to s > 0, ≤ 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.

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.

Parameters

etaL,hL,qxL,qyL	left cell free surface, depth, unit discharge
etaR,hR,qxR,qyR	right cell
nx,ny	unit normal L→R
h_dry	depth below which a cell's velocity is zero
out	flux (x/y frame), positive L→R
corrL_x,corrL_y	out: bed-slope correction for L, ½g(h*_L² − h_L²)·n̂ (per unit face length; multiply by ξ·Δt)
corrR_x,corrR_y	out: for R, ½g(h*_R² − h_R²)·(−n̂)

Returns

true when the face carries any flux (at least one side wet after reconstruction); false ⇒ every output is zero.

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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

Face flux from RECONSTRUCTED side states (RECONSTRUCTION_ORDER 2).

The free surface and velocities are the MUSCL-extrapolated face values and the bed stays piecewise constant per cell (z_side = η_cell − h_cell); the bed-slope correction uses the reconstructed face depth, so at rest (zero gradients) the face reduces exactly to the first-order well-balanced form.

Parameters

etaLf,uxLf,uyLf	left face-extrapolated free surface and velocity
zL,hL_cell	left cell bed and cell-mean depth
etaRf,...	right side likewise

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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.

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

L,R	reconstructed side states (h*, un, ut)
fh	out: mass flux (m²/s), positive L→R
fn	out: normal-momentum flux (m³/s²)
ft	out: tangential-momentum flux (m³/s²)
sstar	out: contact speed (m/s)

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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].

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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.

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Variable Documentation

kGravity

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

inlineconstexpr