Discharge cavitation

From GAWDAwiki

Discharge cavitation, also known as recirculation cavitation, results from changing pressure at the point of exit, the discharge valve. The valve cannot allow the liquid to pass through quickly enough, so the currents' varying speeds create tiny changes in the uniform pressure. Even these small variations can create the ideal circumstances for cavitation.^[1]

References

1. http://www.wisegeek.com/what-is-cavitation.htm