Column separation (DGCM)

When transient head falls to vapor pressure the liquid column separates and a vapor cavity forms, then collapses with an implosion spike. Modelled by the discrete (gas) cavity method.

When a computed head drops to the vapor head, we clamp it there and open a discrete vapor cavity whose volume integrates the net flow in/out. When the cavity collapses back to zero, the columns rejoin and an implosion pressure spike appears. Interior sections, valve nodes, and multi-pipe junctions are all first-class cavity sites; non-cavitating paths stay byte-identical.