Resistance and wake distortion optimization of JBC considering ship-propeller interaction

Abstract

In this paper, the self-propulsion performance of a full formed hull is optimized by the in-house hull form optimization software OPTShip-SJTU 2.1. In the field of hull form optimization, complex hull optimizations such as hull-propeller interaction optimization have not launched a full investigation. To break through this limitation, the hull-propeller interaction module is brought into the software. We conduct a hull-propeller interaction design optimization of Japan Bulk Carrier (JBC) with an actual propeller (AP) based on CFD considering ship resistance and propeller wake distortion at Fr = 0.142. Hull form deformation module is applied to change the stern shape of the JBC. The in-house CFD software naoe-FOAM-SJTU is applied to calculate the hull resistance and wake fraction. The dynamic overset grid method is used to achieve the interaction between hull and propeller and obtain the high-fidelity flow field during the optimization processing. A multi-objective genetic algorithm (NSGA-II) is applied to obtain the optimized hull forms based on the Kriging surrogate model. The influences of propeller for the flow field around stern are also studied. Results indicate: (I) OPTShip-SJTU 2.1 can optimize the coupled hydrodynamic performance in complex hull form optimization. (II) The hull resistance and wake fraction have a strong positive correlation under the deformation setting in this paper. (III) Contraction of hull line at the stern can suppress the flow separation around the stern which is benefit for reducing the pressure resistance and improving the propeller wake distortion. (IV) It is necessary to consider the interaction between propeller and hull together in hull form optimization. The interactions between the shape of stern, propeller performance, and flow field around stern are discussed preliminary, which provide several references for the subsequent research.