Experimental investigation of the effect of inward and outward propeller rotation on single blade and propeller loads

This paper is a sequel of the experimental investigation presented in Ortolani and Dubbioso (2019a) that addressed the single blade and propeller loads during the steady phase of the turning circle. In particular, the effect of inward and outward propeller sense of revolution on the propulsive performance has been investigated for a twin screw ship model equipped with a novel set-up pursued for the measurements of the single blade loads. On the basis of previous numerical investigations (Muscari et al., 2017; Dubbioso et al., 2022), the propeller sense of revolution should be evaluated as a passive mean to mitigate the amplification of the mean or fluctuating component of the blade loads and associated side effects (i.e., noise) caused by blade-wake interactions that occur during maneuvering conditions. The understanding and the accurate quantification of propeller loads, in these realistic operative scenario, is pivotal to design low emission and comfortable ships, fulfilling the requirements of safety and continuity of operations at sea. The analysis is carried out revisiting the investigation in Ortolani and Dubbioso (2019a) for the approach speed at F=0.26 and a large set of rudder angles that span from moderate to tight maneuvers.