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OpenSWMM Engine
6.0.0-alpha.4
Data-oriented, plugin-extensible SWMM Engine (6.0.0-alpha.4)
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OpenSWMM Engine
6.0.0-alpha.4
Data-oriented, plugin-extensible SWMM Engine (6.0.0-alpha.4)
|
Exact cross-section geometry — area, top width and wetted perimeter as closed forms of the section's defining dimensions. More...
Go to the source code of this file.
Namespaces | |
| namespace | openswmm |
| namespace | openswmm::fv |
| namespace | openswmm::fv::secgeom |
| namespace | openswmm::fv::secgeom::detail |
Functions | |
| double | openswmm::fv::secgeom::detail::circTheta (double r, double y) |
| Evaluate the central angle of a circular water segment. | |
| double | openswmm::fv::secgeom::detail::circArea (double r, double y) |
| Evaluate the exact wetted area of a circular segment. | |
| double | openswmm::fv::secgeom::detail::circWidth (double r, double y) |
| Evaluate the exact circular free-surface chord width. | |
| double | openswmm::fv::secgeom::detail::circPerim (double r, double y) |
| Evaluate the exact submerged circular arc length. | |
| template<class F> | |
| double | openswmm::fv::secgeom::detail::simpsonStep (F &f, double a, double b, double fa, double fm, double fb, double whole, double eps, int depth) |
| Recursively refine a cached Simpson panel to an absolute error target. | |
| template<class F> | |
| double | openswmm::fv::secgeom::detail::integrate (F f, double a, double b, double eps=1.0e-12, int depth=40) |
| Integrate a scalar function with adaptive Simpson quadrature. | |
| double | openswmm::fv::secgeom::detail::ellipsePerim (double ax, double by, double y) |
| Integrate the submerged arc of a mathematical ellipse. | |
| bool | openswmm::fv::secgeom::hasClosedForm (int type) |
| Identify shapes with an analytic area/width and direct or quadrature perimeter here. | |
| bool | openswmm::fv::secgeom::isPolynomialOpen (int type) |
| Identify open sections represented by quadratic area and linear perimeter. | |
| double | openswmm::fv::secgeom::areaOfDepth (const XSectParams &xs, double h) |
| Evaluate per-barrel flow area for the FV closure builder. | |
| double | openswmm::fv::secgeom::widthOfDepth (const XSectParams &xs, double h) |
| Evaluate per-barrel top width including the invert boundary value. | |
| double | openswmm::fv::secgeom::perimeterOfDepth (const XSectParams &xs, double h) |
| Evaluate per-barrel wetted perimeter for FV geometry sampling. | |
| double | openswmm::fv::secgeom::hydRadOfDepth (const XSectParams &xs, double h) |
| Evaluate per-barrel hydraulic radius for the FV closure builder. | |
Variables | |
| constexpr double | openswmm::fv::secgeom::kPi = 3.14159265358979323846 |
| constexpr double | openswmm::fv::secgeom::kRectAlfMax = 0.97 |
Exact cross-section geometry — area, top width and wetted perimeter as closed forms of the section's defining dimensions.
Build-time only (plan FV1D_CLOSURE_KERNEL_PERF_PLAN_2026-09-11 §2a′): the FV closure tables are sampled from these functions, never from the legacy 51-row lookup tables, so the solver's geometry is the section to interpolation accuracy rather than to table accuracy. Full-precision π; no legacy operand-order constraints — this header is not under the dynamic-wave bit-parity contract and must not be used by the dynamic-wave path.
Closed forms exist for CIRCULAR, FORCE_MAIN, FILLED_CIRCULAR, RECT_CLOSED, RECT_OPEN, TRAPEZOIDAL, TRIANGULAR, PARABOLIC and POWERFUNC (hasClosedForm). Every other shape — the composites RECT_TRIANG / RECT_ROUND / MOD_BASKET, the table-defined ARCH / EGGSHAPED / HORSESHOE / GOTHIC / CATENARY / SEMIELLIPTICAL / BASKETHANDLE / SEMICIRCULAR, and the transect shapes IRREGULAR / CUSTOM / STREET — is evaluated through the legacy evaluator, whose table (or piecewise formula) is that shape's definition. The closure built from them still gains the derivative pair T ≡ dA/dh and I₁ ≡ ∫A, which the legacy tables lack.
HORIZ_ELLIPSE and VERT_ELLIPSE are table-defined on purpose: SWMM's elliptical pipes are the standard elliptical concrete-pipe profiles, not mathematical ellipses — measured against a true ellipse of the same height and width, the legacy 3×4 ft horizontal section carries 21 % more full area and a different perimeter. Treating them as ellipses would silently change what the shape keyword means.
Everything here is a plain function over XSectParams, host-only (acos, adaptive quadrature), and may be freely reused by a later dynamic-wave program under its own gates.
1.13.2