Higher order rotating cavitation in an inducer

In the present study, a higher order rotating cavitation predicted by the stability analysis was identified through the measurements of inlet pressure fluctuations and blade stress fluctuations. The propagation speed ratio of the higher order rotating cavitation is about 5, and the amplitude of the blade stress fluctuation at the root of leading edge caused by the rotating cavitation is the same level as the conventional rotating cavitation. The higher order rotating cavitation occurred at higher cavitation number compared with that of conventional rotating cavitation. A higher order cavitation surge was also observed at the transition point from the conventional to the higher order rotating cavitation. It was clarified that these cavitation instabilities can be suppressed by modifying the shape of the inlet casing.