A method for predicting propeller performance considering ship motion in regular waves

Abstract

The capacity of the propulsion engine is reduced due to the Energy Efficiency Design Index (EEDI) regulations, so more precise prediction of the propulsion performance is required. The heave and pitch motions of ships are main influences on propeller performance in waves. Therefore, this study investigated the effect of a propeller's immersion depth and tilt angle on the propeller performance in calm water and in waves. Numerical simulations of propeller open water test were performed with several immersion depths, tilt angles, heave motion, and pitch motion. Model tests were also carried out at several immersion depths and tilt angles. A prediction method was then developed to predict the performance of a propeller with motion in waves. Variation of the propeller performance due to the immersion depth and tilt angle in calm water was applied as a function of the advance ratio (J) and immersion depth (h/D), including the effects of waves and motion. The performance of a propeller with heave motion in waves was predicted using the completed estimation equation. Even though the fluctuation width could not be predicted, the trends were very similar. The results of this study could be considered useful for predicting a ship's performance in waves.