Analysis of the strut-foil system

One of the distinguishing features of SEA-BUS is the presence of struts piercing the free surface, regardless the operation speed. Their role is to feed the water-jet propulsion system and to provide control by suitable appended lifting devices. Here, the flow around struts with appended lifting devices is numerically studied to detect possible interaction effects. Upon ruling out separation phenomena, the flow is assumed inviscid and irrotational and lifting effects are recovered by introducing wakes of vanishingly small thickness. Further, bodies are generally assumed ''fully wetted''. Therefore possible occurrence of cavitation and ventilation are completely neglected. Free surface deformations are assumed small. On this ground, a velocity potential can be introduced and the flow around lifting bodies piercing or beneath a free surface results in a problem for the Laplace equation with boundary conditions of various nature. The numerical solution is expediently achieved by re-writing the problem in terms of boundary integral equations. Results for the complete problem are discussed, while results aimed to check the algorithm and main discretization equations are collected.