A multiple Green's function expression for the hydrodynamic analysis of multi-hull structures

Abstract

A modified Green's function expression in a multiple function form is developed to evaluate the hydrodynamic coefficients of two-dimensional multi-hull structures floating or fixed in a seaway. Regrettably in conventional singularity methods applied to mono-hulls, twin-hulls, etc., irregular frequencies arise in the numerical analysis. It is shown that when the modified Green's function is used, the numerical analysis is free of irregular frequencies, the numerical accuracy of the results below the lowest irregular frequency is the same as derived from the conventional approach and the physical phenomenon of resonant surface wave interaction is retained in the theory. Results are presented for symmetric and asymmetric twin hull configurations as well as a rectangular mono-hull section heeled to an angle of 15°. A comparison between results evaluated from conventional and modified singularity approaches is also included.