6. Noise generated by cavitation

6.1 Nature and origin of the phenomenon

Cavitation is due to the passage of a greater or lesser fraction of the pumped liquid into the vapour phase. It initially appears in precise, limited zones where pressure is low and reaches vapor pressure. Cavitation noise therefore exists only under specific conditions, when the pressure P ₀ at the pump suction falls below a certain threshold.

Cavitation noise is caused by the implosion of bubbles or vapour pockets, either on themselves or on a wall. Bubbles implode when they move from a low-pressure zone to a high-pressure zone. The local value of the pressure gradient, at the point where the bubbles close, determines the violence of the phenomenon and the resulting noise...