Presets
Playback
Plumbing
Conduit depth, radius and the side chamber.
Heat and water
Hot-rock power, groundwater recharge and its temperature.
Setting
Altitude sets the surface pressure; time warp speeds up the clock.
Layers
Model checks
The science
What happens
A geyser is a hot-spring plumbing system in which the weight of the water column decides when the water may boil. Hot rock heats the bottom of a water-filled conduit; the water cannot boil because the pressure there is high. When a little water at the top is lost the pressure drops, the deep water becomes superheated, flashes into steam, throws out more water and the pressure drops further: an eruption.
Equations
Hydrostatic pressure at depth z: p(z) = p0 + rho g z with rho about 960 kg/m3. The local boiling temperature T_b(p) comes from the IAPWS-IF97 saturation equation. Heating: dT/dt = P / (m c) with c = 4180 J/(kg K). Flashing converts superheat to steam: x = c (T - T_b) / L, with L from Watson's correlation (2257 kJ/kg at 100 C).
Over one eruption cycle the stored energy returns to its start, so P x interval = H_out - recharge enthalpy + losses. The interval therefore scales with the enthalpy that each eruption carries away divided by the heating power.
Honest simplifications
The model is one vertical dimension with 48 cells, constant specific heat and density, no dissolved gas (real geysers also use CO2), steam leaves instantly at the vent and the side chamber is a single widened section. The 2D view uses the same engine module as the 3D page; numbers match exactly. The jet is drawn as a stylised spray scaled to the computed height.
Checks in the page
Check 1 compares the IF97 boiling point against steam-table values from 1 to 40 bar. Check 2 compares the hydrostatic pressure of a full conduit with p0 + rho g D. Check 3 runs the current plumbing headlessly and compares the eruption interval with the energy balance, plus the energy and mass ledger closure.
What to try
- Watch the temperature profile creep towards the boiling curve in graph 1: the first point to touch it triggers the eruption.
- Choose Same geyser at sea level: the boiling curve moves right, so more heat is stored and the interval changes.
- Choose Cold groundwater recharge: every degree has to come from the hot rock, so the interval roughly doubles.
- Raise the heating power to 2 MW: the cycle disappears and a continuous spouter remains.