Mutual hydrodynamic interaction between the operating propeller and the rudder

The paper presents a description of the algorithm and computer program developed for numerical analysis of the hydrodynamic interaction between operating propeller and ship rudder. The program is based on unsteady lifting surface model representing the propeller and on boundary element model representing the rudder. The program accepts arbitrary geometry of both the rudder and the propeller as the input data. Interaction with the ship hull is taken into account in the form of given non-uniform velocity field of the ship wake. The mutual hydrodynamic interaction is taken into account by simultaneous solution of the unsteady kinematic boundary condition on both objects. The results of calculation include time-dependent pressure distribution on the propeller and on the rudder together with fluctuating hydrodynamic forces on both objects. Apart from that the program is capable of detecting and describing the dynamic development of different forms of the cavitation phenomena on the propeller and on the rudder. The paper includes the results of calculation of the hydrodynamic characteristics and cavitation phenomena of different propeller-rudder configurations. These results are compared with experimental data wherever available. This comparison confirms the effectiveness of the described computation method as the tool for design and analysis of the propeller-rudder configurations.