[35] Cavitation
Motion energy is required
for an increase in the flow velocity of the oil at a restriction.
This motion energy is derived from the pressure energy. If the
vacuum which results is smaller than -30 kPa (-0.3 bar), air
dissolved in the oil is precipitated out. When the pressure rises
again due to a reduction in speed, the oil bursts into the gas
bubbles.
Cavitation is a significant factor in hydraulic systems as a cause of wear in devices and connections.