Image-based measurements for examining model predictability of cavitation on a marine propeller surface

Because of its complex nature, cavitation associated with marine propellers poses a challenge to numerical simulations for predicting it. This paper experimentally examines the predictions of vapor volume fraction (VVF) done by RANS simulations with three cavitation models for a propeller whose design is to suppress sheet cavitation. The equality of VVF and cavitation occurrence probability (COP), whose distribution can be measured with cavitation images acquired using the phase-locked imaging technique in an open-water test, is found and becomes the base of a methodology developed for examining model predictability of cavitation. By comparing and correlating the distributions of VVF computed using different cavitation models with that of measured COP, predictabilities of cavitation models can be quantified to elucidate modeling issues and possible remedies for them.