Presets
Playback
Shape
Iceberg and water
Melt, waves, damping
Side melt narrows the berg faster than it shortens it, so it can roll over.
Model checks
The science
Archimedes and stability
A floating body displaces its own weight of water: ρi A = ρw Asub, so a rectangular berg floats with draught d = (ρi/ρw) H, about 90 % below the surface. The buoyancy force acts at the centre B of the submerged shape, computed here by clipping the rotated polygon against the waterline; the weight acts at the centre of gravity G.
Metacentric height
For small heel the restoring torque is ρw g V · GM · sinθ with GM = KB + BM - KG, BM = I/V. For a rectangle GM = d/2 + W²/(12 d) - H/2, which changes sign at W/H = √(6 ρ(1 - ρ)) with ρ = ρi/ρw (about 0.75 for glacier ice in sea water). Below it the upright position is unstable and the berg capsizes to a new stable orientation.
Honest simplifications: 2D rigid block (per metre of length), no surge or sway, added mass and drag are constant factors, waves are small-amplitude long waves that only move and tilt the local waterline (no diffraction), melt is a simple shrinking rule, and real icebergs are fractured, non-uniform and calve.
What to try
- Press Tall pillar capsizes, then Stable tabular berg: only the width-to-height ratio changed.
- Run Melting makes it flip and watch the red dot (GM) cross zero on the middle graph before the roll starts.
- Use Pinnacle in swell and raise the wave amplitude to excite the roll.