We give a hydrodynamical explanation for the chaotic behaviour of a dripping
faucet using the results of the stability analysis of a static pendant drop and a
proper orthogonal decomposition (POD) of the complete dynamics. We find that the
only relevant modes are the two classical normal forms associated with a saddle–
node–Andronov bifurcation and a Shilnikov homoclinic bifurcation. This allows
us to construct a hierarchy of reduced-order models including maps and ordinary
differential equations which are able to qualitatively explain prior experiments and
numerical simulations of the governing partial differential equations and provide
an explanation for the complexity in dripping. We also provide a new mechanical
analogue for the dripping faucet and a simple rationale for the transition from
dripping to jetting modes in the flow from a faucet.