Tank Emptying Time

Variable-head drain through an orifice (Torricelli)

Inputs

Variable-head drain through an orifice or short nozzle (Torricelli). Time to fall from H1 to H2, and time to empty.

Tank surface area

m²

Orifice diameter

Discharge coefficient C_d

Sharp orifice ≈ 0.62

Initial head H1

Final head H2

0 to empty

Same Cd orifice equation

Variable-head overflow