Hydrodynamic performance of a full-scale ship with a Pre-Swirl Duct: A numerical study with partially rotating grid method

Abstract

This study investigates the hydrodynamic performance of a full-scale KVLCC2-S ship fitted with a Pre-Swirl Duct using CFD simulations. Four different propeller rotation representations are employed to evaluate the impact of the Pre-Swirl Duct on the ship’s performance. The study introduces a partially rotating grid method for two-phase flows, implemented within the Naval Hydro Pack library based on foam-extend software. The results of the study reveal that prediction of power savings depends on the accuracy of the numerical propeller representation. Non-inertial, partial, and inertial propeller representations predicted power savings while the actuator disc method predicted increase in delivered power. The partially rotating grid method provides a less computationally expensive alternative to the inertial propeller rotation representation, but at the cost of reduced accuracy. Furthermore, the study challenges the conventional analysis that attributes the power savings to improved propeller-hull interaction, suggesting that increased propeller efficiency is the primary cause.