Functions
int	translateShape (XsectShape link_shape)
	Translate LinkData::XsectShape to batch XSectShape int code.

double	getVelocity (const XSectParams &xs, double flow, double depth, int barrels=1)
	Compute flow velocity from flow and depth.

double	getFroude (const XSectParams &xs, double v, double y)
	Compute Froude number from velocity and depth.

void	computeConveyance (double roughness, double slope, double s_full, double &beta, double &rough_factor, double &q_full)
	Compute Manning conveyance coefficients for a conduit.

double	getDepthFromFlow (const XSectParams &xs, double beta, double q)
	Compute normal-flow depth from flow rate (inverse Manning).

double	getCapacity (const XSectParams &xs, double depth)
	Compute the capacity fraction (depth / full depth for conduits, setting for other links).

double	getHydPower (double flow, double head_upstream, double head_downstream)
	Compute hydraulic power dissipated in a link.

XSectParams	buildXSectParams (const LinkData &links, std::size_t uj, const std::vector< transect::TransectData > *transects=nullptr)
	Build XSectParams from LinkData SoA arrays.

void	applyTabulatedXSectParams (XSectParams &xs, const transect::TransectData &td, double y_full, int transect_idx)
	Derive the full-flow properties of a tabulated cross-section.

Function Documentation

◆ applyTabulatedXSectParams()

void openswmm::link::applyTabulatedXSectParams	(	XSectParams &	xs,
		const transect::TransectData &	td,
		double	y_full,
		int	transect_idx )

Derive the full-flow properties of a tabulated cross-section.

The counterpart of xsect::setParams() for the three shapes whose geometry comes from a transect table rather than a formula: IRREGULAR, CUSTOM and STREET_XSECT. Fills the y_full/a_full/r_full/ w_max/s_full/s_max/a_bot/yw_max fields of xs from the built table, and attaches the table pointers.

Beyond a/r/w_full this sets the PHYSICAL s_max and a_bot (the area at the maximum section factor), which drive link_getYnorm's getAofS normal-depth solve and the flow limit q_max. Leaving s_max = s_full and a_bot = 0 diverges every transect whose section factor peaks below full depth.

Note: PARITY: legacy getTransectParams (xsect.c:1339-1358) for IRREGULAR / STREET_XSECT, and setCustomXsectParams (xsect.c:668-700) for CUSTOM. xs.type must already be set to the batch XSectShape code.

Parameters

xs	[in/out] Params to fill; `type` must be set on entry.
td	Built transect table (buildTables / buildCustomTables output).
y_full	Full depth (ft). Used only by CUSTOM, whose table is built at unit height and scaled here; ignored for IRREGULAR/STREET, which take y_full from `td`.
transect_idx	Index to record in `xs.transect`, or -1 when the table is owned rather than pooled.

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◆ buildXSectParams()

XSectParams openswmm::link::buildXSectParams	(	const LinkData &	links,
		std::size_t	uj,
		const std::vector< transect::TransectData > *	transects = nullptr )

Build XSectParams from LinkData SoA arrays.

Parameters

links	Link SoA data.
uj	Link index (size_t).
transects	Optional transect-table pool (ctx.transect_tables). When supplied, IRREGULAR/CUSTOM/STREET_XSECT links get their A/R/W table pointers attached so the per-element accessors can evaluate tabulated geometry. Pass nullptr when the link is known to be a self-contained shape.

Returns: Populated XSectParams struct.

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◆ computeConveyance()

void openswmm::link::computeConveyance	(	double	roughness,
		double	slope,
		double	s_full,
		double &	beta,
		double &	rough_factor,
		double &	q_full )

Compute Manning conveyance coefficients for a conduit.

Sets:

beta = PHI * sqrt(|slope|) / roughness
rough_factor = GRAVITY * (roughness / PHI)^2
q_full = s_full * beta

Parameters

	roughness	Manning's n.
	slope	Conduit slope (rise/run).
	s_full	Section factor at full depth (ft^8/3).
[out]	beta	Manning conveyance factor.
[out]	rough_factor	Head loss coefficient.
[out]	q_full	Full-pipe flow rate (ft3/s).

◆ getCapacity()

double openswmm::link::getCapacity	(	const XSectParams &	xs,
		double	depth )

Compute the capacity fraction (depth / full depth for conduits, setting for other links).

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◆ getDepthFromFlow()

double openswmm::link::getDepthFromFlow	(	const XSectParams &	xs,
		double	beta,
		double	q )

Compute normal-flow depth from flow rate (inverse Manning).

Given Q, find y such that Q = beta * S(y). S = Q / beta → A = getAofS(xs, S) → y = getYofA(xs, A).

Parameters

xs	Cross-section parameters.
beta	Manning conveyance factor.
q	Flow rate (ft3/s).

Returns: Normal depth (ft).

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◆ getFroude()

double openswmm::link::getFroude	(	const XSectParams &	xs,
		double	v,
		double	y )

Compute Froude number from velocity and depth.

Fr = |V| / sqrt(g * D_h) where D_h = A/T (hydraulic depth). Returns 0 for dry or fully-full closed conduits.

Parameters

xs	Cross-section parameters.
v	Velocity (ft/s).
y	Water depth (ft).

Returns: Froude number (dimensionless).

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◆ getHydPower()

double openswmm::link::getHydPower	(	double	flow,
		double	head_upstream,
		double	head_downstream )

Compute hydraulic power dissipated in a link.

P = gamma * Q * hL where gamma = specific weight of water, Q = flow rate, hL = head loss across link. hL = friction slope * length (for conduits).

See also: Legacy: link_getPower() in link.c

Parameters

flow	Flow rate (ft3/s).
head_upstream	Head at upstream node (ft).
head_downstream	Head at downstream node (ft).

Returns: Power (ft-lbs/s). Divide by 550 for horsepower.

◆ getVelocity()

double openswmm::link::getVelocity	(	const XSectParams &	xs,
		double	flow,
		double	depth,
		int	barrels = 1 )

Compute flow velocity from flow and depth.

V = Q / (barrels * A(y)), where A is the cross-sectional area. Returns 0 if depth < 0.01 ft or area < FUDGE.

Parameters

xs	Cross-section parameters.
flow	Flow rate (ft3/s).
depth	Water depth (ft).
barrels	Number of identical barrels (default 1).

Returns: Velocity (ft/s).

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◆ translateShape()

int openswmm::link::translateShape ( XsectShape link_shape )

Translate LinkData::XsectShape to batch XSectShape int code.

The two enums have different orderings. This function provides a safe mapping for use wherever XSectParams.type is set from LinkData::xsect_shape.

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Functions

Function Documentation

◆ applyTabulatedXSectParams()

◆ buildXSectParams()

◆ computeConveyance()

◆ getCapacity()

◆ getDepthFromFlow()

◆ getFroude()

◆ getHydPower()

◆ getVelocity()

◆ translateShape()