When a fluid passes a valve the fluid velocity increases and the pressure drops according the Bernoulli equation.

[h=Cavitation]3[/h] If the speed through the valve is high enough, the pressure in the liquid may drop to a level where the fluid may start bubble or flash. The pressure recovers sufficiently and the bubbles collapse upon themselves.

Cavitation may be noisy but is usually of low intensity and low frequency. This situation is extremely destructive and may wear out the trim and body parts of the valve in short time.

  • The Cavitation Number An introduction to and a definition of the Cavitation Number.
  • Cavitation - an Introduction