Classes
struct	Design
	One inlet design in INTERNAL units (legacy `TInletDesign`, inlet.c:66-74). More...

struct	Geom
	Street / channel geometry seen by one inlet, in INTERNAL units. More...

struct	InletSoA

class	InletSolver

struct	UsageParams
	The per-placement half of one usage row (legacy `TInlet` fields). More...

Enumerations
enum class	InletType : int { GRATE = 0 , CURB = 1 , COMBO = 2 , SLOTTED = 3 , DROP_GRATE = 4 , DROP_CURB = 5 , CUSTOM = 6 }

enum class	GrateType : int { P_BAR_50 = 0 , P_BAR_50x100 = 1 , P_BAR_30 = 2 , CURVED_VANE = 3 , TILT_BAR_45 = 4 , TILT_BAR_30 = 5 , RETICULINE = 6 , GENERIC = 7 }
	Legacy `enum GrateType` (inlet.c:124-127). More...

enum class	Placement : int { AUTOMATIC = 0 , ON_GRADE = 1 , ON_SAG = 2 }

enum class	ThroatAngle : int { HORIZONTAL = 0 , INCLINED = 1 , VERTICAL = 2 }
	Legacy `enum ThroatAngleType` (inlet.c:131) — `InletStore::curb_throat`. More...

enum class	CurveKind : int { UNRESOLVED = 0 , DIVERSION = 1 , RATING = 2 }
	`InletStore::curve_kind` codes for a CUSTOM design. More...

Functions
double	getEo (double sr, double ts, double w)
	Compute the depressed-gutter flow ratio using HEC-22 Eq4-4.

double	getFlowSpread (const Geom &g, double Q)
	Compute approach flow spread with crown limiting and depressed-gutter iteration.

double	getGutterFlowRatio (const Geom &g, double w)
	Compute the fraction of street flow above a selected gutter width.

double	getGutterAreaRatio (const Geom &g, double grate_width, double area)
	Compute the grate-width correction to depressed-gutter intercepted flow.

double	getSplashOverVelocity (int grate_type, double grate_length)
	Evaluate the standard grate splash-over velocity polynomial.

double	getGrateInletCapture (const Design &d, Geom &g, double Q)
	Compute one on-grade grate's frontal and side capture.

double	getCurbInletCapture (const Geom &g, double Q, double opening_length)
	Compute on-grade curb-opening capture from equivalent cross slope.

double	getOnGradeInletCapture (const Design &d, Geom &g, double Q, double depth)
	Compute a single on-grade inlet or combination sweeper/grate capture.

double	getOnGradeCapturedFlow (const Design &d, const UsageParams &u, Geom &g, double q, double depth)
	Compute series inlet capture across the current street sides.

void	findOnSagGrateFlows (const Design &d, const Geom &g, double depth, double weir_flow, double orifice_flow)
	Compute the active grate weir or orifice contribution for one sag inlet.

double	getCurbOrificeFlow (double flow_depth, double opening_height, double opening_length, int throat_angle)
	Compute sag curb-opening orifice flow using throat-adjusted head.

void	findOnSagCurbFlows (const Design &d, const Geom &g, double depth, double opening_length, double weir_flow, double orifice_flow)
	Compute sag curb-opening weir/orifice contributions with transition blending.

double	getOnSagSlottedFlow (const Design &d, double depth)
	Compute one sag slotted-drain weir or orifice capacity.

double	getOnSagInletCapture (const Design &d, const Geom &g, double depth)
	Combine one sag inlet's grate, sweeper and curb-orifice contributions.

double	getOnSagCapturedFlow (const Design &d, const UsageParams &u, const Geom &g, double depth, int nsides_prev)
	Scale sag capacity using usage factors and legacy carried-over street sides.

double	getCustomCapturedFlow (const UsageParams &u, const Geom &g, const Table &curve, int curve_kind, double q, double depth, double ucf_flow, double ucf_len)
	Compute custom inlet capture from authored diversion or rating curves.

double	getInletArea (const Design &d, const UsageParams &u)
	Compute the usage's effective open inlet area for backflow weighting.

Variables
constexpr double	MIN_RUNOFF_FLOW = 0.001
	Legacy MIN_RUNOFF_FLOW (consts.h:203) — cfs.

constexpr double	INLET_FUDGE = 0.0001
	Legacy FUDGE (consts.h:272).

constexpr double	INLET_BIG = 1.0e10
	Legacy BIG (consts.h:118).

Enumeration Type Documentation

◆ CurveKind

enum class openswmm::inlet::CurveKind : int

strong

InletStore::curve_kind codes for a CUSTOM design.

Enumerator
UNRESOLVED
DIVERSION
RATING

◆ GrateType

enum class openswmm::inlet::GrateType : int

strong

Legacy enum GrateType (inlet.c:124-127).

Enumerator
P_BAR_50
P_BAR_50x100
P_BAR_30
CURVED_VANE
TILT_BAR_45
TILT_BAR_30
RETICULINE
GENERIC

◆ InletType

enum class openswmm::inlet::InletType : int

strong

Legacy enum InletType (inlet.c:119-122) — the COMBO slot is the merged GRATE+CURB design the legacy parser encodes as two [INLETS] lines.

Enumerator
GRATE
CURB
COMBO
SLOTTED
DROP_GRATE
DROP_CURB
CUSTOM

◆ Placement

enum class openswmm::inlet::Placement : int

strong

Legacy enum InletPlacementType (inlet.c:129) — matches the token order of [INLET_USAGE] / [INLET_JUNCTIONS] and InletUsageStore::placement.

Enumerator
AUTOMATIC
ON_GRADE
ON_SAG

◆ ThroatAngle

enum class openswmm::inlet::ThroatAngle : int

strong

Legacy enum ThroatAngleType (inlet.c:131) — InletStore::curb_throat.

Enumerator
HORIZONTAL
INCLINED
VERTICAL

Function Documentation

◆ findOnSagCurbFlows()

void openswmm::inlet::findOnSagCurbFlows	(	const Design &	d,
		const Geom &	g,
		double	depth,
		double	opening_length,
		double *	weir_flow,
		double *	orifice_flow )

Compute sag curb-opening weir/orifice contributions with transition blending.

Uses uniform/long-opening or depressed-gutter weir, then blends toward orifice at1.4*curb_height. Caller supplies nondegenerate transition depths and positive root domains; no automatic output clearing, unit conversion or pointer checks.

Parameters

[in]	d	Borrowed validated inlet design in native ft/ft per second; coefficients/types must match the selected physical design.
[in]	g	Borrowed native street/channel geometry with positive physical slopes/roughness/dimensions needed by the chosen branch.
[in]	depth	Nonnegative finite local water depth ft unless explicitly stated otherwise.
[in]	opening_length	Curb length ft; <=0 leaves both outputs unchanged, DROP_CURB multiplies it by4.
[in,out]	weir_flow	Non-NULL cfs destination initialized by caller; untouched on pure-orifice/no-opening branch.
[in,out]	orifice_flow	Non-NULL cfs destination initialized by caller; untouched on pure-weir/no-opening branch.

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◆ findOnSagGrateFlows()

void openswmm::inlet::findOnSagGrateFlows	(	const Design &	d,
		const Geom &	g,
		double	depth,
		double *	weir_flow,
		double *	orifice_flow )

Compute the active grate weir or orifice contribution for one sag inlet.

DROP_GRATE uses all-four-side perimeter; gutter grate adjusts wetted width and mean depth. Transition is depth<=1.79*open_area/perimeter; outputs cfs. Caller supplies positive nondegenerate geometry and valid root/power domains; no full output reset or pointer validation.

Parameters

[in]	d	Borrowed validated inlet design in native ft/ft per second; coefficients/types must match the selected physical design.
[in]	g	Borrowed native street/channel geometry with positive physical slopes/roughness/dimensions needed by the chosen branch.
[in]	depth	Nonnegative finite local water depth ft unless explicitly stated otherwise.
[in,out]	weir_flow	Non-NULL scalar initialized by caller, typically0; assigned only on weir branch, otherwise preserved.
[in,out]	orifice_flow	Non-NULL scalar initialized by caller, typically0; assigned only on orifice branch, otherwise preserved.

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◆ getCurbInletCapture()

double openswmm::inlet::getCurbInletCapture	(	const Geom &	g,
		double	Q,
		double	opening_length )

Compute on-grade curb-opening capture from equivalent cross slope.

Depressed gutters modify equivalent slope through Eo; full-capture length uses HEC-22 Eq4-22a. Requires positive slope/roughness and valid spread; no independent geometry/finite checks.

Parameters

[in]	g	Borrowed native street/channel geometry with positive physical slopes/roughness/dimensions needed by the chosen branch.
[in]	Q	Positive finite approach discharge cfs; low-level formula does not validate it.
[in]	opening_length	Nonnegative curb/slotted opening length ft.

Returns: Approach Q times capture efficiency clamped0..1, cfs.

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◆ getCurbOrificeFlow()

double openswmm::inlet::getCurbOrificeFlow	(	double	flow_depth,
		double	opening_height,
		double	opening_length,
		int	throat_angle )

Compute sag curb-opening orifice flow using throat-adjusted head.

No finite/domain guard or source-flow cap.

Parameters

[in]	flow_depth	Water depth ft; must leave nonnegative head after throat correction.
[in]	opening_height	Positive curb-opening height ft.
[in]	opening_length	Nonnegative effective opening length ft.
[in]	throat_angle	HORIZONTAL subtracts height/2, INCLINED0.7071*height/2; other codes use full depth.

Returns: 0.67*height*length*sqrt(64.32*effective_head), cfs.

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◆ getCustomCapturedFlow()

double openswmm::inlet::getCustomCapturedFlow	(	const UsageParams &	u,
		const Geom &	g,
		const Table &	curve,
		int	curve_kind,
		double	q,
		double	depth,
		double	ucf_flow,
		double	ucf_len )

Compute custom inlet capture from authored diversion or rating curves.

DIVERSION loops replicates on bypassed per-side flow, applying clog, per-inlet limit and bypass upper cap. RATING multiplies depth-curve output by replicates/clog/sides without applying q or flow_limit caps. No name binding, finite check or inventory booking.

Parameters

[in]	u	Borrowed usage with nonnegative replicate count, clog factor0..1 and per-inlet flow_limit cfs (<=0 means unlimited).
[in]	g	Borrowed native street/channel geometry with positive physical slopes/roughness/dimensions needed by the chosen branch.
[in]	curve	Borrowed resolved table with valid shape/sample units; table_lookupEx extrapolation rules apply.
[in]	curve_kind	DIVERSION means captured versus approach flow; RATING means captured versus depth; other codes return0.
[in]	q	Nonnegative native approach flow cfs.
[in]	depth	Nonnegative finite local water depth ft unless explicitly stated otherwise.
[in]	ucf_flow	Positive project-display flow units per cfs, for curve x/y conversion.
[in]	ucf_len	Positive project-display length units per ft, for rating curve depth.

Returns: Native cfs capture across current positive g.nsides.

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◆ getEo()

double openswmm::inlet::getEo	(	double	sr,
		double	ts,
		double	w )

Compute the depressed-gutter flow ratio using HEC-22 Eq4-4.

No finite/domain checks or clamping; caller supplies a physically valid nondegenerate geometry.

Parameters

[in]	sr	Positive gutter-to-street cross-slope ratio, dimensionless.
[in]	ts	Positive spread beyond gutter ft; no zero-denominator guard.
[in]	w	Positive gutter width ft.

Returns: Dimensionless ratio1/(1+sr/((1+sr/(ts/w))^2.67-1)).

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◆ getFlowSpread()

double openswmm::inlet::getFlowSpread	(	const Geom &	g,
		double	Q )

Compute approach flow spread with crown limiting and depressed-gutter iteration.

Undepressed street uses (Q/qfactor)^0.375. Depressed gutter uses a maximum10-update fixed-point solve with0.01ft difference tolerance; last estimate is returned without a convergence flag. Does not assign g.t because geometry is const.

Parameters

[in]	g	Borrowed native street/channel geometry with positive physical slopes/roughness/dimensions needed by the chosen branch.
[in]	Q	Positive finite approach discharge cfs; low-level formula does not validate it.

Returns: Top width/spread ft, capped above by g.t_crown.

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◆ getGrateInletCapture()

double openswmm::inlet::getGrateInletCapture	(	const Design &	d,
		Geom &	g,
		double	Q )

Compute one on-grade grate's frontal and side capture.

Reads existing spread for street geometry; rectangular/trapezoidal DROP_GRATE may recompute area/depth/width and adjust sx. Uses standard or authored splash velocity and depressed-gutter corrections. This low-level result is not globally clipped to0..Q; outer usage routines apply selected upper caps.

Parameters

[in]	d	Borrowed validated inlet design in native ft/ft per second; coefficients/types must match the selected physical design.
[in,out]	g	Borrowed native geometry; capture routines may update spread t and channel cross-slope sx. Borrowed xs must remain live for the call.
[in]	Q	Positive finite approach discharge cfs; low-level formula does not validate it.

Returns: Native cfs capture from HEC-22 efficiency formulas.

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◆ getGutterAreaRatio()

double openswmm::inlet::getGutterAreaRatio	(	const Geom &	g,
		double	grate_width,
		double	area )

Compute the grate-width correction to depressed-gutter intercepted flow.

Uses precomputed spread and gutter slopes; no generic denominator/finite guard.

Parameters

[in]	g	Borrowed native street/channel geometry with positive physical slopes/roughness/dimensions needed by the chosen branch.
[in]	grate_width	Positive effective grate width ft.
[in]	area	Positive total flow cross-section area ft2; denominator after subtracting outside-gutter area must remain positive.

Returns: Dimensionless grate/gutter flow-area ratio, with1 for full-width coverage.

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◆ getGutterFlowRatio()

double openswmm::inlet::getGutterFlowRatio	(	const Geom &	g,
		double	w )

Compute the fraction of street flow above a selected gutter width.

No flow calculation, spread refresh or finite/range checks.

Parameters

[in]	g	Borrowed native street/channel geometry with positive physical slopes/roughness/dimensions needed by the chosen branch.
[in]	w	Positive width ft; g.t is already computed flow spread.

Returns: 1 when spread<=w, otherwise depressed-gutter Eo or1-(1-w/t)^2.67.

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◆ getInletArea()

double openswmm::inlet::getInletArea	(	const Design &	d,
		const UsageParams &	u )

Compute the usage's effective open inlet area for backflow weighting.

Adds grate openings and curb length exceeding grate length; positive slotted length replaces that sum with slot area. Does not multiply street sides or validate dimensions.

Parameters

[in]	d	Borrowed validated inlet design in native ft/ft per second; coefficients/types must match the selected physical design.
[in]	u	Borrowed usage with nonnegative replicate count, clog factor0..1 and per-inlet flow_limit cfs (<=0 means unlimited).

Returns: Native ft2 open area times replicate count and clog factor.

◆ getOnGradeCapturedFlow()

double openswmm::inlet::getOnGradeCapturedFlow	(	const Design &	d,
		const UsageParams &	u,
		Geom &	g,
		double	q,
		double	depth )

Compute series inlet capture across the current street sides.

Requires positive g.nsides. Divides approach per side, evaluates replicates on remaining bypass, applies clog/per-inlet limit and bypass upper cap, then multiplies sides. Stops when remaining per-side flow is below MIN_RUNOFF_FLOW; geometry spread can change during evaluation.

Parameters

[in]	d	Borrowed validated inlet design in native ft/ft per second; coefficients/types must match the selected physical design.
[in]	u	Borrowed usage with nonnegative replicate count, clog factor0..1 and per-inlet flow_limit cfs (<=0 means unlimited).
[in,out]	g	Borrowed native geometry; capture routines may update spread t and channel cross-slope sx. Borrowed xs must remain live for the call.
[in]	q	Finite approach cfs; q<MIN_RUNOFF_FLOW or zero replicates returns0.
[in]	depth	Nonnegative finite local water depth ft unless explicitly stated otherwise.

Returns: Total native cfs captured across g.nsides.

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◆ getOnGradeInletCapture()

double openswmm::inlet::getOnGradeInletCapture	(	const Design &	d,
		Geom &	g,
		double	Q,
		double	depth )

Compute a single on-grade inlet or combination sweeper/grate capture.

DROP_CURB uses sag capacity and DROP_GRATE grate capacity, each upper-limited to Q. SLOTTED uses curb capture. Street combinations compute positive curb length ahead of grate, then grate on remaining Q, refreshing spread as needed. No universal lower clamp or donor inventory booking.

Parameters

[in]	d	Borrowed validated inlet design in native ft/ft per second; coefficients/types must match the selected physical design.
[in,out]	g	Borrowed native geometry; capture routines may update spread t and channel cross-slope sx. Borrowed xs must remain live for the call.
[in]	Q	Positive finite approach discharge cfs; low-level formula does not validate it.
[in]	depth	Nonnegative finite local water depth ft unless explicitly stated otherwise.

Returns: Native cfs capture before usage clog/replicate/flow-limit scaling.

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◆ getOnSagCapturedFlow()

double openswmm::inlet::getOnSagCapturedFlow	(	const Design &	d,
		const UsageParams &	u,
		const Geom &	g,
		double	depth,
		int	nsides_prev )

Scale sag capacity using usage factors and legacy carried-over street sides.

Zero replicates returns0. Does not cap by current approach/disposable volume; caller applies routing-model limits. Previous-side ordering deliberately preserves legacy shared-state behavior.

Parameters

[in]	d	Borrowed validated inlet design in native ft/ft per second; coefficients/types must match the selected physical design.
[in]	u	Borrowed usage with nonnegative replicate count, clog factor0..1 and per-inlet flow_limit cfs (<=0 means unlimited).
[in]	g	Borrowed native street/channel geometry with positive physical slopes/roughness/dimensions needed by the chosen branch.
[in]	depth	Finite signed depth ft; absolute value is used for sag capacity.
[in]	nsides_prev	Nonnegative side count from previously processed inlet, not necessarily g.nsides; product with num_inlets must fit int.

Returns: Sag capacity cfs after clog/per-inlet limit, multiplied by nsides_prev*num_inlets.

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◆ getOnSagInletCapture()

double openswmm::inlet::getOnSagInletCapture	(	const Design &	d,
		const Geom &	g,
		double	depth )

Combine one sag inlet's grate, sweeper and curb-orifice contributions.

Positive slotted length takes precedence. Otherwise sums grate/sweeper weir+orifice and only curb-orifice overlap when grate is in orifice mode; excludes overlapping curb-weir contribution to match legacy. No donor cap or validation.

Parameters

[in]	d	Borrowed validated inlet design in native ft/ft per second; coefficients/types must match the selected physical design.
[in]	g	Borrowed native street/channel geometry with positive physical slopes/roughness/dimensions needed by the chosen branch.
[in]	depth	Nonnegative finite local water depth ft unless explicitly stated otherwise.

Returns: Native cfs capacity before usage scaling.

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◆ getOnSagSlottedFlow()

double openswmm::inlet::getOnSagSlottedFlow	(	const Design &	d,
		double	depth )

Compute one sag slotted-drain weir or orifice capacity.

Uses2.48*length*depth^1.5 below threshold,0.8*length*width*sqrt(64.32*depth) above. No clog, replicate or approach-flow cap here.

Parameters

[in]	d	Borrowed validated inlet design in native ft/ft per second; coefficients/types must match the selected physical design.
[in]	depth	Nonnegative finite local water depth ft unless explicitly stated otherwise.

Returns: Native cfs, switching at depth=2.587*slotted_width.

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◆ getSplashOverVelocity()

double openswmm::inlet::getSplashOverVelocity	(	int	grate_type,
		double	grate_length )

Evaluate the standard grate splash-over velocity polynomial.

Polynomial is not clamped to nonnegative values; generic designs use their separate authored splash velocity.

Parameters

[in]	grate_type	Standard fitted type0..6; GENERIC or out-of-range selects0.
[in]	grate_length	Physical grate length ft.

Returns: Fitted velocity ft/s, or0 for an unsupported curve.

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Variable Documentation

◆ INLET_BIG

double openswmm::inlet::INLET_BIG = 1.0e10

inlineconstexpr

Legacy BIG (consts.h:118).

◆ INLET_FUDGE

double openswmm::inlet::INLET_FUDGE = 0.0001

inlineconstexpr

Legacy FUDGE (consts.h:272).

◆ MIN_RUNOFF_FLOW

double openswmm::inlet::MIN_RUNOFF_FLOW = 0.001

inlineconstexpr

Legacy MIN_RUNOFF_FLOW (consts.h:203) — cfs.

Classes

Enumerations

Functions

Variables

Enumeration Type Documentation

◆ CurveKind

◆ GrateType

◆ InletType

◆ Placement

◆ ThroatAngle

Function Documentation

◆ findOnSagCurbFlows()

◆ findOnSagGrateFlows()

◆ getCurbInletCapture()

◆ getCurbOrificeFlow()

◆ getCustomCapturedFlow()

◆ getEo()

◆ getFlowSpread()

◆ getGrateInletCapture()

◆ getGutterAreaRatio()

◆ getGutterFlowRatio()

◆ getInletArea()

◆ getOnGradeCapturedFlow()

◆ getOnGradeInletCapture()

◆ getOnSagCapturedFlow()

◆ getOnSagInletCapture()

◆ getOnSagSlottedFlow()

◆ getSplashOverVelocity()

Variable Documentation

◆ INLET_BIG

◆ INLET_FUDGE

◆ MIN_RUNOFF_FLOW