kavitaation

Kavitaation, commonly referred to as cavitation, is the formation, growth, and subsequent collapse of vapor-filled cavities in a liquid when local pressure falls below the liquid’s vapor pressure. When surrounding pressure returns, these cavities collapse violently, generating shock waves, microjets, and heat. The process can occur in any liquid system where rapid pressure changes or high flow velocities occur.

Two main forms are recognized. Inertial (transient) cavitation involves rapid bubble growth and violent collapse, often producing strong acoustic emissions and surface damage. Non-inertial (gas) cavitation involves the growth and persistence of gas-filled bubbles under sustained low-pressure conditions, typically causing less immediate damage but potential performance degradation over time. Cavitation can also involve heterogeneous nucleation on solid surfaces or gas pockets within defects.

Causes include rapid pressure fluctuations due to high-velocity flow, abrupt geometry changes (valves, throttles, and impellers), blade-pass interactions on propellers, and exposure to intense ultrasonic fields. Environmental factors such as temperature, dissolved gas content, and fluid properties also influence cavitation onset and severity.

Effects range from nuisance noise, vibration, and reduced efficiency to material erosion, pitting, and structural damage of hydraulic machinery. In controlled settings, cavitation is exploited for beneficial uses such as ultrasonic cleaning, emulsification, and medical lithotripsy, as well as certain machining and material processing techniques.

Measurement and modeling rely on acoustic emissions, high-speed imaging, and pressure sensing, while numerical tools like the Rayleigh–Plesset equation and computational fluid dynamics help predict bubble dynamics. Mitigation focuses on design changes to avoid low-pressure regions, increase system pressure, smooth flow paths, and use materials with higher cavitation resistance. The term kavitaation is a transliteration variant used in some languages for the same phenomenon.