Experimental and numerical studies on resistance of a catamaran vessel with non-parallel demihulls

In common catamaran vessels, demihulls are parallel to each other. in this paper, the total resistance of a catamaran vessel with non-parallel demihulls is investigated experimentally and numerically. experiments are carried out at different separation ratios (s.r.), that is the ratio of fore to aft separation of the catamaran demihulls; and also in two ratios of length to separation in amidships (l=sm). the fluent solver, based on the finite volume method (fvm), was used for numerical solution. applying the vof model, the free surface around the catamaran vessel and total resistance are calculated and compared with experimental results. finally, the frictional resistance of the catamaran fromthe ittc 1957 correlation line is calculated and compared with cfd frictional resistance. the results show that non-parallel demihulls cause total resistance to increase at froude numbers below 0.8, and decrease at froude numbers over 0.8. in the numerical part, at low froude numbers, numerical results have an error up to 10% relative to model test results, but error increases at high froude numbers up to 25%.