DynamicWave.cpp File Reference

Dynamic wave routing – batch-oriented St. Venant equations. More...

#include "DynamicWave.hpp"
#include "Node.hpp"
#include "Outfall.hpp"
#include "XSectBatch.hpp"
#include "ForceMain.hpp"
#include "Culvert.hpp"
#include "../core/Constants.hpp"
#include "../core/SimulationContext.hpp"
#include "../core/UnitConversion.hpp"
#include "../math/SIMD.hpp"
#include <cmath>
#include <algorithm>
#include <cstdlib>
#include <numeric>

Include dependency graph for DynamicWave.cpp:

Namespaces
namespace	openswmm
namespace	openswmm::dynwave

Variables
constexpr double	openswmm::dynwave::SQRT_GRAVITY
	sqrt(GRAVITY) — precomputed to avoid per-element std::sqrt in Froude calc.
constexpr double	openswmm::dynwave::INV_SQRT_GRAVITY
	1.0 / sqrt(GRAVITY) — multiply instead of divide in Froude computation.

Detailed Description

Dynamic wave routing – batch-oriented St. Venant equations.

The solver follows this pattern per Picard iteration:

1. computeLinkGeometry() – batch call to XSectGroups for ALL links:
   • depth1/depth2 from node heads and link offsets
   • Preissmann slot geometry applied when depth > y_full (closed conduits)
   • XSectGroups::computeAreas/HydRad/Widths for free-surface depths
   • Slot area/width/hrad overrides for surcharged depths
2. solveMomentumBatch() – pure array arithmetic over ALL links:
   • velocity = old_flow / area_mid (vectorisable)
   • Froude from velocity and hydraulic depth (vectorisable)
   • sigma (inertial damping) from Froude (vectorisable)
   • full inertial damping when closed conduit is surcharged
   • friction slope dq1 = dt * roughFactor / rMid^(4/3) * |v| (vectorisable)
   • head gradient dq2 = dt * g * aMid * (h2-h1)/L (vectorisable)
   • momentum update: q = (qOld - dq2 + dq3 + dq4) / (1 + dq1)
   • under-relaxation (vectorisable)
3. updateNodeFlows() – scatter link flows to node inflow/outflow
4. updateNodeDepths() – per-node Picard convergence check
   • EXTRAN surcharge: dQ/dH with smooth transition near crown
   • Separate convergence tracking for surcharged vs free-surface nodes

Note

Legacy reference: src/legacy/engine/dwflow.c, dynwave.c

Author

Caleb Buahin caleb.nosp@m..bua.nosp@m.hin@g.nosp@m.mail.nosp@m..com

Copyright

Copyright (c) 2026 Caleb Buahin. All rights reserved.

License\n MIT License