A study on the added resistance of a catamaran advancing in waves considering variations of both operating and geometric parameters

The study focuses on the analysis of the added resistance of a catamaran advancing both in regular waves and in a seaway. The numerical simulation has been carried out within the framework of potential flow theory by using a three dimensional, linear, Rankine source-based Boundary Element Method (BEM) and a Near-Field approach based on pressure integration for the first-order motions and the second-order longitudinal force prediction, respectively. A preliminary validation and verification study on both a mono-hull and a catamaran is proposed. A systematic analysis of the effect of some relevant operating and geometric parameters on the added resistance performance of a catamaran in waves is presented. Variations of the operating and geometric parameters include the advancing speed, the encounter angles from head to beam waves, the hull static trim and the demi-hulls separation. The trends of the added resistance pseudo-RAO are discussed in the light of the comparison against the reference design condition highlighting possible worse and optimal configurations.