η(t) = η₀ + A cos(2πt / T + φ)

η₀ = 0.75 m · A = 1.35 m · T = 12.42 h · φ = 0

Model range: 2A = 2.70 m. The water surface follows a single sinusoidal constituent to demonstrate a semi-diurnal tide. The gauge reports water level minus the procedural seabed height at the marked tidal-flat point.

Assumptions: idealised periodic tide; fixed mean level; one dominant constituent; constant local gravity (9.81 m/s²). The day slider advances model time and does not represent a real tide prediction.

Simplifications: no wind setup, storm surge, river discharge, bathymetric coupling, currents, friction, multiple tidal constituents, or lunar/solar ephemeris. Coastline inundation is a visual water-plane intersection, not a hydraulic simulation.

Closed-form checks available as window.__selfTest().