Comparative analysis of the hydrodynamic performance of untwisted and twisted rudders using a hybrid RANSE/BEM model

Results of a computational study on the hydrodynamic performance of twisted and untwisted rudders for a single screw vessel are presented. Ship flow simulations are performed by using a hybrid RANSE/BEM model. Numerical predictions by RANSE and BEM solvers are validated through comparisons against experimental datafor the ship considered in the study. The comparative analysis of untwisted and twisted rudders is carried out by fully-appended ship flow simulations at uniform ship speed and rudder angles between 0 and 20 degree. Numerical results predict comparable manoeuvring capabilities for the alternative layouts, whereas the twisted design allows to mitigate negative peaks observed on the untwisted rudder surface over a range of helm angle.