Impact of Tunnel Stern Design on Hydrodynamic Characteristics of Catamarans

Abstract The growth in worldwide maritime activities has resulted in the extensive use of catamarans for passenger and cargo transportation. This study investigates the influence of stern tunnel modifications on catamarans, emphasising their unique design and hydrodynamic features. Computational fluid dynamics (CFD) is used to assess resistance and flow around the hull. Initially, the length, depth, and width of the tunnel were determined as design parameters based on the main dimensions of an original NPL 4A model. Single-hull forms are produced based on these parameters, with nine different stern tunnel configurations. The flow behaviour around the hull was determined by solving the Reynolds-averaged Navier-Stokes equations using the Ansys Fluent commercial software within a Froude number range 0.3-1.0. Subsequently, double-hull analyses are conducted using the best-performing model, in terms of resistance from the single-hull analyses. The results demonstrate that all single-hull designs achieve resistance reductions of up to 39% compared to the original model. The optimal hull form, in terms of resistance performance, similarly showed up to 15% reduction in resistance when applied to the double-hull configuration.