Numerical analysis of effect of asymmetric stern of ship on its screw propeller efficiency

Abstract

During designing the ship its designer tends to achieve as-high-as possible efficiency of ship’s propulsion system. The greatest impact on the efficiency is introduced by ship’s screw propeller whose efficiency depends not only on its geometry but also distribution of wake current velocity. To change wake current distribution and improve propeller efficiency an asymmetric form is usually applied to stern part of ship hull. This paper presents results of numerical analysis of wake current velocity distribution, performed by using a CFD method for a B 573 ship of symmetric stern and the same ship of an asymmetric stern. Next, the mean values of screw propeller efficiency in non-homogenous water velocity field were calculated for both the hull versions of B 573 ship.