Analysis of propeller bearing loads by CFD. Part II: Transient maneuvers

The numerical study presented in Part I (Dubbioso et al., 2017) on the bearing loads developed by the propellers of a twin screw model during quasi-steady conditions is extended to transient maneuvers. In the previous study, numerical simulations highlighted that the hydrodynamic loads might experience significant peak at moderate turning rates due to complex interaction of the propeller with the wake. In the present paper, the complete turning circle maneuver at δ=35∘ at Fr=0.265 is numerically simulated in order to analyze the character of the blade loads during the transient phases after the actuation of the rudder (start and pull-out). The analysis shows that the overall degradation of the propeller performance may occur also at kinematic conditions weaker than those usually considered as the most critical ones (in general, tight maneuvers); therefore, these conditions should be accounted for also in the early design phases.