Theory 66/Engineering & infrastructure/Cavitation
Cavitation Is Suction Against Vapour
The claim
Cavitation begins when the ratio of local suction head to vapour pressure head falls below one, so a turbine can cavitate at one operating point and not another.
01Mechanism
Pressure below vapour pressure nucleates vapour cavities that collapse downstream.
02Prediction
Onset should track the ratio.
03Refutation
Onset tracking flow rate would remove the pressure margin.