Numerical study on characteristic correlation between cavitating flow and skew of ship propellers

The correlation between ship propellers cavitating flow and their skew is investigated numerically using several propellers with different skew angle. With a hybrid grid strategy and sliding mesh, an RANS solver is applied to predict the vapor volume fraction and the pressure in propeller wake. The numerical predictions of the cavitation for the propeller E779A agree with the corresponding measured data in general. Under the operating condition of high blade loading, sheet cavitation becomes weak with the increase of the propeller skew angle. On the contrary, under the operating condition of low cavitation number, the sheet cavitation becomes strong with the increase of the skew. The hub cavitation is turned into strong with the increase of the skew at all the conditions. The proper increase of the propeller skew may well control propeller cavitation performance. The characteristics of the pressure signal in propeller wake coincide with the parameters of geometric model and the operating condition. Their amplitudes of the low frequency line spectra of pressure signal in propeller wake could be related to the propellers skew angle. More specifically, the amplitude of the low frequency line spectra for the highly skewed propeller seems to be linearly reduced with increased frequency.