Hydraulic operating point
Hₚ(Q) = z + hₜ − Hₛ + hᶠ + hᵥ. The flow rate is found by bisection over the pump curve and the system head curve.
Pipe and storage
v = Q/A; hᶠ = f(L/D)(v²/2g); dh/dt = (Qin − Qout)/Aₜ.
Leak and energy
Qₗ = CᵈAₗ√(2gH); P = ρgQH/η.
All values use SI units internally. This is an educational, quasi-steady approximation, not an engineering design tool.
- Constant friction factor f = 0.025; valve loss uses an illustrative K relation.
- Incompressible water, lumped tanks, fixed pump curve and idealised orifice leakage.
- Rainfall is supplied as prescribed runoff pulses. Water hammer, cavitation and sediment are omitted.
- Some scene geometry and weather motion are visual only; they do not change the hydraulic solver.
g = 9.81 m/s²; ρ = 1000 kg/m³; Cᵈ = 0.62 (approximate).