Numerical study on motion and added resistance of a trimaran advancing in waves based on hybrid Green function method

Abstract

In present study, a three dimensional panel method was proposed to investigate the motion and added resistance of a trimaran advancing with forward speed in waves. The panel method is based on potential theory and hybrid Green function, for which, the whole domain is divided into two subdomains. In these two domains, the first order Taylor Expansion Boundary Element Method (TEBEM) and translating-pulsating panel source Green function method is adopted, respectively. With respect to this hybrid method, the convergent results can be obtained at a relatively small computational domain size. Four methods to evaluate the added resistance of the trimaran are taken into consideration, such as momentum conservation method, radiation energy method and direct integration method. Present numerical methods are firstly validated through comparison with measured data for two Wigley ship hulls. Then numerical results of present trimaran hull are compared to those of experiments, and good agreement can be obtained for different simulation cases. Furthermore, the interference factor for different forward speeds are analyzed. Meanwhile, the influence of outrigger layout on the motions, added resistance and interference factors are discussed in detail.