Numerical investigation of propeller induced hull pressure pulses using RANS and IDDES

Paper in proceeding, 2021

This paper investigates the numerical predictions of pressure pulses induced by a cavitating marine propeller operating in behind-hull condition in model scale. Simulations are performed using the commercial package Star-CCM+ using RANS and IDDES approaches. The predicted sheet cavitation agreed well compared to experimental recordings and the 1st- and 2ndorder blade passing frequency (BPF) pressure pulses also agreed well compared to measurements via pressure transducers mounted on the model scale ship hull. Tip vortex cavitation (TVC)
bursting was observed in the experiments and predicted as well in the numerical simulations. A traveling re-entrant jet from blade leading edge to blade tip was predicted underneath the sheet cavity structure, and triggered the partly collapse of sheet cavitation and strong TVC
dynamics. The hull pressure uctuations are found to be correlated with the rate of cavitation volume growth/shrinkage and the TVC dynamics are found generating high levels of higherorder BPF pressure pulses, according to the deduced TVC volume time series. Significant cavitation variations were recorded between blade passings and propeller revolutions in the experiments, while in the numerical predictions no noticeable cavitation difference was predicted, and the predicted 3rd- to 5th-order BPF pressure pulse tonal values are generally higher than experimental measurements. The cavitation variations in the experiments are suspected to be related with sheet cavitation inception rather than blade loading difference induced by wake dynamics.