concept

Cavitation

The tearing of water into vapour-filled voids when local pressure falls to its vapour pressure — boiling from tension rather than heat, as flow accelerates over a curved surface. The damaging part is not their formation but their collapse: swept into higher pressure they implode asymmetrically, driving micro-jets that strike nearby surfaces at 1–5 GPa, enough to pit ship propellers and living tissue alike. For dolphins and fast fish the cavitation speed ceiling in surface water is roughly 10–15 m/s. Because ambient pressure rises with depth, that ceiling rises with the square root of depth — which makes the deep ocean the one place a very fast jet does not destroy itself.