Influence of different hull–propeller relative position configuration on the self-propelled hydrodynamic performance of catamaran

As an important technological branch in the field of autonomous surface vehicles, unmanned catamarans play a crucial role in ocean resource development, oceanographic research, and polar exploration. This study investigates the influence of the relative position between the hull and propeller on the hydrodynamic characteristics of an unmanned catamaran during self-propulsion. It is the first time to systematically analysis the hydrodynamic effects of relative position, including axial position, vertical position, lateral position, and shaft inclination angle. The self-propulsion hydrodynamic performance of the catamaran is conducted through a combined approach of computational fluid dynamics numerical simulation and experimental research. The findings indicate that the axial position has the most significant impact on instantaneous resistance fluctuation and the rotational speed at the self-propulsion point, particularly when the propeller is located within the strong vortex region near the stern. The vertical position primarily affects the sinkage and trim motion of the hull. The lateral position within a specific range induces strong asymmetric flow, leading to a notable increase in resistance and trim angle. For the inclination angle, when the inclination angle exceeds 6°, it not only significantly changes the flow structure between the propellers but also has a significant impact on the attitude. Finally, through sensitivity analysis, the paper provides constructive suggestions for the arrangement of propellers on catamarans.