Numerical and Experimental Investigation into the Resistance of Warship Catamaran at Various Speeds and Separation Distances

Abstract

The prioritization of naval vessel construction in Indonesia underscores the nation's commitment to safeguarding its territorial waters. As part of this endeavour, optimizing ship hull design is essential to ensure safety, efficacy and minimize environmental impacts. In line with this objective, Indonesia is currently developing a tank-boat with a catamaran hull configuration, meticulously engineered to navigate diverse maritime environments, from shallow waters to deep seas. To evaluate the performance of this innovative vessel, Computational Fluid Dynamics (CFD) is employed for both numerical analysis and practical testing in still-water conditions across various scenarios. The study investigates the effects of lateral separation ratios (S/L) ranging from 0.2 to 0.4 and speed fluctuations represented by the Froude Number spanning from 0.1 to 1.0. The findings from this investigation reveal boat remarkable resilience in still-water situations, particularly when compared to experimental trials. Notably, the results indicate a consistent increase in performance from Froude Number (Fr) 0.1 to 1.0. It is observed that the total resistance coefficient (CT) peaks in still-water conditions at a Froude number (Fr) of 0.5, suggesting optimal performance at this speed. The alignment between CFD predictions and experimental findings, with differences well within acceptable margins, validates the robustness of the computational models. The highest value of the total resistance coefficient (CT) in still water was observed at a Froude number (Fr) of 0.5 across different lateral separation ratios (S/L). It peaked at Fr 0.5 with an S/L of 0.3 in both CFD and experimental analyses. In CFD, the CT value was 18.16 x 10-3, while in the experimental analysis, it was 18.83 x 10-3, indicating discrepancy of 3.68 % which is an excellent agreement between the two methods.